Nanoenergy Advances doi: 10.3390/nanoenergyadv6020015

Authors: Yitian Song Pei Chen Chunyu Huang Shouhua Yang Boqin Li Guojun Pei Jie Liang Wencai Peng Feng Yu

The valorization of biomass waste into advanced electrode materials presents a promising pathway toward sustainable electrochemical energy storage. Herein, a silicon-doped carbon material (Si-CTS-Carbon) is synthesized from chitosan via an in situ reaction with silicon tetrachloride (SiCl4) and subsequent controlled pyrolysis. When evaluated as an anode for lithium-ion batteries (LIBs), Si-CTS-Carbon exhibits a high reversible capacity of 509.2 mAh g−1 with 99% capacity retention after 100 cycles at 0.05 A g−1. For sodium-ion battery (SIB) applications, it achieves a stable reversible capacity of 155.4 mAh g−1 under identical conditions. Structural and electrochemical analyses reveal that the robust C–O–Si covalent network effectively accommodates volume variation of silicon and enhances structural integrity during cycling. Furthermore, the hierarchically porous architecture shortens ion diffusion pathways, leading to improved Li+/Na+ transport kinetics. This work demonstrates a viable strategy for fabricating high-performance battery anodes by synergistically doping silicon into biomass-derived carbon, enabling practical biowaste valorization for energy storage.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6020014

Authors: Zhaoying Lu Enchen Wan Kai Zhou Jiayu Miao Xiaoyu Zhao Liang Xiao

Sodium metal batteries (SMBs) are promising energy storage systems, yet their practical application is hindered by unstable solid electrolyte interphases (SEIs) and safety issues associated with flammable electrolytes. Although the flame-retardant solvent trimethyl phosphate (TMP) is widely used in rechargeable batteries, its application in SMBs remains constrained due to uncontrolled and accumulated parasitic reactions with sodium metal anodes. Here, we propose a novel synergistic strategy that combines a fluorinated additive (FEC) with a low-cost, high-concentration NaClO4 to stabilize the electrode–electrolyte interface in TMP-based electrolytes. This approach enables the formation of a robust, NaF-rich SEI while restructuring the Na+ solvation sheath to coordinately trap TMP molecules, thereby suppressing parasitic reactions between sodium metal and TMP. As a result, the Na|Na3(VOPO4)2F cell achieves exceptional cycling stability with 89.04% capacity retention over 1000 cycles at 1C. This work provides a cost-effective and practical pathway toward safe and long-lasting SMBs using non-flammable phosphate electrolytes.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6020013

Authors: Guoqing Yang Siyu Zhao Na Lin Jiahuan Zhao Haoyu Zhang Panpan Zhao Wenying Zhou

As a prospective two-dimensional conductive filler, titanium carbide (MXene) can remarkably boost the dielectric constant (ε) of polymer composites at low loadings. Nevertheless, the accompanied large dielectric loss (tan δ) and leakage current greatly limit their practical applications in dielectric-related fields. To tackle this dilemma, an organic polydopamine (PDA) shell was coated on an MXene surface via a self-polymerization method, and the dielectric properties of PDA-modified MXene/poly(vinylidene fluoride) (PVDF) were explored. The findings show that, in comparison to unmodified MXene/PVDF, MXene@PDA/PVDF retains a high ε and improved breakdown strength (Eb). It further realizes a notable decrease in both tan δ and electrical conductivity. The introduced PDA interlayer serves to effectively separate adjacent MXene nanosheets, which inhibits the development of conductive paths and introduces charge traps to restrict carrier migration, thus reducing tan δ. Further, the interlayer not only improves the interfacial compatibility, but also mitigates strong dielectric mismatch between MXene and PVDF, which facilitates the homogeneous redistribution of the local electric field, contributing to enhanced Eb. Theoretical fitting and simulation studies unlock the profound polarization mechanisms and charge migration modulated by the PDA interlayer. The resulting Mxene@PDA/PVDF exhibits concurrently elevated ε (35.68) and enhanced Eb (12.94 kV/mm), as well as low tan δ (0.34) at 103 Hz and 7 wt% filler loading, which is not achievable in neat MXene/PVDF. This work demonstrates that core–shell interfacial engineering offers an effective strategy for designing flexible polymer dielectrics with superior dielectric performances, showcasing potential applications in energy storage, advanced power systems and flexible electronics.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6010012

Authors: Yutong Lin Huilin Lan Qinghe Zhao Luyi Yang Zheyuan Liu Chengkai Yang

The increasing demand for higher energy density in lithium-ion batteries has driven significant interest in layered oxide cathode materials. However, their development is hindered by an inherent trade-off between structural stability and ion transport kinetics. This compromise often manifests as a conflict between achieving high capacity, long cycle life, and excellent rate performance. Consequently, mitigating structural degradation and minimizing interfacial side reactions have emerged as core research priorities. Based on this, this review summarizes the crystal chemistry and key challenges of three main types of layered oxide cathode materials, and critically evaluates two main modification strategies: bulk doping, which enhances performance by regulating the electronic structure and suppressing phase transitions; and surface coating, which builds a protective layer at the particle–electrolyte interface to suppress side reactions and metal dissolution. Looking ahead, in terms of modification, the focus should be on multi-scale co-doping to construct a stable bulk phase structure and multi-functional coating to optimize the interface. Integrating artificial intelligence with high-throughput computation will powerfully enable the pursuit of these advanced modification strategies. This integrated approach may resolve the fundamental contradiction between energy density and stability, thereby paving a new pathway for next-generation lithium-ion batteries.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6010011

Authors: Glenda Ribeiro de Barros Silveira Lacerda Luiz P. Fagundes dos Santos Nathany Lopes Oliveira Sousa Gabriel Jácomo de Paula Tonon Maria Luiza M. Rocco Tulio Matencio Hállen Daniel Rezende Calado Paulo F. Ribeiro Ortega Garbas Anacleto dos Santos Junior

A hybrid material based on the copolymerization of EDOT (3,4-ethylenedioxythiophene) and Py (pyrrole), 1:1 monomer ratio, onto multi-walled carbon nanotubes (MWCNTs) was synthesized through a multistep functionalization approach. The resulting P(EDOT-co-Py)@MWCNT hybrid, poly(3,4-ethylenedioxythiophene-co-pyrrol)@MWCNT hybrid, was characterized by Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). These characterizations confirmed the successive functionalization steps, the effective anchoring of the monomers, and the subsequent formation of the copolymer. Transmission electron microscopy (TEM) images revealed a homogeneous polymer coating along the nanotube surface while preserving the structural integrity of the MWCNTs throughout the functionalization and polymerization processes. The P(EDOT-co-Py)@MWCNT hybrid was evaluated as an active electrode material for aluminum-ion storage in an aqueous aluminum sulfate electrolyte. The system exhibited two distinct charge-storage mechanisms: at high current densities, proton surface adsorption dominated, whereas at lower rates, a faradaic contribution associated with polymer chain redox activity and the reversible extraction/insertion of Al3+ became prevalent. The hybrid electrode delivered high specific capacities, reaching 200.6, 106.3, and 44.3 mAh g−1 at 0.10, 0.25, and 0.50 A g−1, respectively. These values are comparable to—or even exceed—those reported for similar cathodic materials designed for Al3+ storage, highlighting P(EDOT-co-Py)@MWCNT hybrid as a highly promising cathode candidate for aqueous aluminum-ion energy-storage systems.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6010010

Authors: Peihua Chen Ruiqin Tan Maria Nazir Jia Li Weijie Song

NiO electrochromic films have significant potential for applications in smart windows, displays, energy-efficient buildings, and portable electronics, owing to their excellent electrochemical stability, favorable optical modulation performance, and environmental friendliness. However, several challenges remain, such as limited long-term durability, stability under extreme environmental conditions, and the cost-effectiveness of large-scale production. Future research efforts should focus on enhancing the cyclic stability and environmental adaptability of NiO films, developing low-cost fabrication techniques, and advancing multifunctional composite materials for smart devices. This review summarizes recent advances in the preparation and performance optimization of NiO electrochromic films. Several key fabrication methods—including magnetron sputtering, hydrothermal synthesis, electrodeposition, chemical bath deposition, sol–gel processing, and spray pyrolysis—are highlighted, and their effects on film structure, thickness uniformity, and optical properties are analyzed. Furthermore, the critical role of different electrolytes (inorganic, organic, and gel-based) in the electrochromic process is discussed, with a comparative evaluation of their influence on the electrochromic performance of NiO films. This article offers a comprehensive overview of the progress in high-performance NiO electrochromic films and provides theoretical insights and technical support for their broader application in renewable energy and smart home technologies.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6010009

Authors: Weiying Zhang Qi Wu Tian Liao Niuniu Guo Shiyu Liu Shaoqin Peng Yuexiang Li

It is of great significance to prepare carbon-supported non-noble metal catalysts for hydrogen evolution reaction (HER) via a sustainable method. Meanwhile, the enhanced metal-support interaction (MSI) is vital for promoting the catalytic activity of metal/carbon catalysts. Herein, we prepare a biomass-derived porous carbon-supported metal Ni catalyst (Ni/APC) with the enhanced MSI via atomic Ni-N4 sites utilizing agaric as a precursor. The highly dispersed Ni-N4 species preferentially adsorb dye molecules and reactant H2O, beneficial to efficient electron transfer and promoting H2O dissociation. Meanwhile, Ni nanoparticles undertake the active sites for H2 desorption. In virtue of the synergistic effect of metal Ni nanoparticles and atomic Ni-N4 for different roles of active sites, Ni/APC catalysts show more effective dye-sensitized photocatalytic HER activities, compared with pure Ni and pure APC. The Ni/APC catalyst with an optimal Ni loading amount exhibits a high AQY of 41.0% with an excellent long-term stability in terms of both HER activity and structure. It is the first report of an application for biomass-derived carbon catalysts in dye-sensitization hydrogen production, and the synergistic effect of atomic Ni and particled Ni on the dye-sensitized photocatalytic HER is deeply investigated. This work provides new deep insight into the design of new non-noble metal/carbon materials by taking advantage of biomass materials.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6010008

Authors: Xiaojing Wu Huijuan Dong Yingni Zhou Ce Zhou Hong Xia Fushen Lu Muwei Ji

Energy obtained by green ways with releasing environmental pollution is still a challenge for sustainable development for model society. Among energy technologies, photothermal conversion by using solar energy has become a new field and a hot topic in recent years. Based on the exploration of nanomaterials in the past decades, photothermal nanomaterials by using nanomaterials bring new chances for expending the utilization of green energy with high efficiency, mainly including metal semiconductors and carbon nanomaterials. Their modulated structure for enhancing light absorption, accelerating transformation of photon into heat, and located heat management were also considered important for promoting the utilization of solar energy and therefore, the strategies for designed and controllable preparing of photothermal nanomaterials were also summarized. The applications of photothermal nanomaterials were also reviewed to reveal the new chances for energy conversion engineering or promoting the solar energy utilization of solar energy in some cold regions or somewhere with low solar irradiation.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6010007

Authors: Shiqi Zhong Zhiqiang Liu Xiaolong Li Fancheng Meng Xiangfeng Wei Jiehua Liu

Rechargeable zinc–air batteries (ZABs) are still impeded by the intrinsically sluggish kinetics of oxygen reduction and evolution reactions (ORR/OER) and by the instability or prohibitive price of state-of-the-art noble metal catalysts. Metal–organic frameworks (MOFs) have recently emerged as versatile sacrificial templates for next-generation air–cathode electrocatalysts. By programming pyrolytic or chemical conversion pathways, MOFs can be quantitatively transformed into hierarchically porous, heteroatom-doped carbon scaffolds that embed uniform metal, alloy, or metal-oxide nanodomains. The resulting architectures couple metallic conductivity with molecular-scale active site tunability, delivering exceptional ORR/OER activity, stability, and mass transport properties. This review critically examines the most recent advances in MOF-derived electrocatalysts for ZABs, establishing quantitative structure–composition–performance relationships across mono-, bi-, and multi-metallic systems. Emphasis is placed on deciphering how framework topology, metal–ligand coordination, and post-synthetic parameters dictate the density, electronic structure, and accessibility of surface-active moieties during catalyst evolution. We further dissect engineering strategies that enhance intrinsic activity via electronic modulation, bolster durability through encapsulation effects, and optimize hierarchical porosity for rapid O2/water transport. This article concludes by outlining unresolved challenges and future research directions, including atomically precise active site construction, multi-scale compositional control, long-term reversibility under realistic ZABs cycles, scalable and green synthesis, providing a roadmap for translating MOF-derived catalysts from laboratory curiosities to commercially viable air–cathode materials.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6010006

Authors: Gennady N. Panin

The emergence of advanced low-dimensional materials of the graphene family opens up unique opportunities for energy-efficient and fast processing of electrical and optical signals in a wide spectral range from ultraviolet to infrared. Non-volatile resistive states in memristors based on two-dimensional (2D) crystals, 1D nanoribbons, and 0D quantum dots are accessible for control by light and an electric field due to polarization and rearrangement of sp2-sp3 hybridization of carbon atoms, as well as due to photoinduced phase transitions. Two-dimensional materials possess unique structural and electronic properties required for the development of highly efficient nanoenergy memristor devices for low-energy information technology. This article discusses memristors and photomemristors based on graphene, graphene oxide, diamane, and chalcogenide semiconductors such as MoS2, WSe2, MoS2−xOx, which are structurally similar to graphene and have a 2D layered structure. Memristors based on graphene and graphene oxide, bigraphene, and diamane, fabricated using localized electron irradiation, exhibit nonlinear behavior and well-controlled memristive states associated with sp2-sp3 transitions of carbon atoms under low-power conditions. The review highlights the dual role of graphene as an active material and electrode, as well as the redox control mechanism. Due to a well-controlled redox process, graphene-based devices exhibit the dynamic behavior required for neuromorphic computing directly in the sensor, reducing the energy and time costs associated with data processing. Neuromorphic computing in a photomemristor-based sensor enables the creation of a compact nano-energy system for real-time information recognition in a wide spectral range, similar to biological vision, for use in self-driving cars, personalized medicine, and other applications.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6010005

Authors: Bogdan-Ovidiu Taranu Radu Banica Florina Stefania Rus

The increasing global energy demand and its negative environmental impact created the need for substantial changes in the energy infrastructure. A hydrogen-based infrastructure appears to be the most promising way to secure a clean and safe energy future. Water electrolysis is a method that can be used to generate green hydrogen, but suitable electrocatalysts are required for large-scale applications. This work investigates the electrocatalytic activity of electrodes modified with novel TiO2 nanotube-based electrocatalysts for water electrolysis. The focus was on the hydrogen evolution reaction (HER), and the electrodes that displayed the highest activity were the ones obtained with the procedure consisting of the growth of TiO2 nanotubes on a Ti plate by anodization, the subsequent deposition of MoO2 and Ni(OH)2, and a thermal treatment performed under different conditions. The results of the HER experiments performed in a strong alkaline environment showed that the electrode obtained via vacuum heat treatment exhibited the lowest overpotential value, of 238 mV at i = −10 mA/cm2. Furthermore, the electrode was electrochemically stable, and inter-electrode reproducibility tests revealed only a small variation of the HER overpotential.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6010004

Authors: Rahul Agrawal Kashif Mushtaq Daniel López Pedrajas Iqra Irfan Breogán Pato-Doldán

Freshwater scarcity is increasing day by day and has already reached a threatening level, especially in remotely populated areas. One of the technological solutions to this rising concern could be the use of the solar-based humidification–dehumidification (SHDH) method for water desalination. This technology is a promising solution but has challenges such as solar intermittency. This challenge can be solved by integrating SHDH with the phase change material as a solar energy storage medium. Therefore, a novel nano-enhanced binary eutectic phase change material (NEPCM) was developed in this project. PCM consisting of 70 wt.% stearic acid (ST) and 30 wt.% suberic acid (SBU) with a varying concentration of silicon carbide (SiC) nanoparticles (NPs) (0.1 to 3 wt.%) was synthesized specifically considering the need of SHDH application. The systematic thermophysical characterization was conducted to investigate their energy storage capacity, thermal durability, and performance consistency over repeated cycles. DSC analysis revealed that the addition of SiC NPs preserved the thermal stability of the NEPCM, while the phase transition temperature remained nearly unchanged with a variation of less than 0.74%. The value of latent heat is inversely related to the nanoparticle concentration, i.e., from 142.75 kJ/kg for the base PCM to 131.24 kJ/kg at 3 wt.% loading. This corresponds to reductions in latent heat ranging between 0.98% and 8.06%. The FTIR measurement confirms that no chemical reactions or no new functional groups were formed. All original functional groups of ST and SBU remained intact, showing that incorporating the SiC NP to the PCM lead to physical interactions (e.g., hydrogen bonding or surface adsorption). The TGA analysis showed that the SiC NPs in the NEPCM act as supporting material, and its nano-doping enhanced the final degradation temperature and thermal stability. There was negligible change in thermal conductivity for nanoparticle loadings of 0.1% and 0.4%; however, it increased progressively by 5.2%, 10.8%, 23.12%, and 25.8% at nanoparticle loadings of 0.7%, 1%, 2%, and 3%, respectively, at 25 °C. Thermal reliability was analyzed through a DSC thermal cycling test which confirmed the suitability of the material for the desired applications.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6010003

Authors: Dmitry D. Spasov Ruslan M. Mensharapov Matvey V. Sinyakov Darya E. Grineva Nataliya A. Ivanova Xiang Li Chuanyu Sun Leonid A. Kulikov Daria A. Makeeva Sergey A. Grigoriev

High-temperature proton exchange membrane systems (HT-PEM) based on polybenzimidazole (PBI) membranes are a promising technology offering significant advantages over their low-temperature counterparts. A key challenge limiting its long-term durability is the leaching of phosphoric acid (PA) from the membrane during operation. This work introduces, for the first time, the strategy of modifying polybenzimidazole (PBI) membranes with amino-functionalized porous aromatic frameworks (PAF-20-NH2) to fundamentally enhance their PA retention and operational stability, a critical challenge for high-temperature PEM technologies. We propose that the synergistic combination of the framework’s nanoscale porosity and the specific interaction of its amino groups create an unprecedented network for acid immobilization via reinforced hydrogen bonding. A comprehensive study of the membranes’ physicochemical and structural properties reveals that PAF-20-NH2 modification results in a significant and quantitatively demonstrated improvement in acid retention capacity, directly translating into a notable increase in proton conductivity compared to both pristine PBI and membranes modified with the non-functionalized PAF-20. These findings establish a new, highly effective pathway for the rational design of next-generation high-performance PBI-based membranes.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6010002

Authors: Serikzhan Opakhai Asset Kabyshev Marzhan Kubenova Zhassulan Zeinulla Bakytbek Mauyey Saira Sakhabayeva

This review examines modern approaches to layer formation in solid oxide fuel cells (SOFCs), focusing on traditional, thin-film, and additive manufacturing methods. A systematic comparison of technologies, including slip casting, screen printing, CVD, PLD, ALD, HiPIMS, inkjet, aerosol, and microextrusion printing, is provided. It is shown that traditional methods remain technologically robust but are limited in their capabilities for miniaturization and interfacial architecture design. Modern thin-film and additive approaches provide high spatial accuracy, improved ion-electron characteristics, and flexibility in the design of multilayer structures; however, they require addressing issues related to scalability, ink stability, interfacial compatibility, and reproducibility. Particular attention is paid to interfacial engineering methods, such as functionally graded layers, nanostructured infiltration, and temperature-controlled 3D printing. Key challenges are discussed, including thermal instability of materials, the limited gas impermeability of ultra-thin electrolytes, and degradation during long-term operation. Development prospects lie in the integration of hybrid methods, the digitalization of deposition processes, and the implementation of intelligent control of printing parameters. The presented analysis forms the basis for further research into the scalable and highly efficient production of next-generation SOFCs designed for low-temperature operation and long-term operation in future energy systems.

Nanoenergy Advances doi: 10.3390/nanoenergyadv6010001

Authors: Zhen Tian Jiacheng Liu Chang Ding Changyu Yang Muqing Chen Xiaoming Chen Qiang Liu Li Su

With the advancement of Internet of Things (IoT) technology, flexible sensors with dual optoelectronic sensing modes have emerged as a research hotspot for next-generation smart devices, further driving the urgent demand for environmentally friendly functional materials. Here, we innovatively integrated wastepaper recycling technology with a polyethyleneimine (PEI)-assisted pulping strategy to develop a novel cellulose-based sustainable photo-triboelectric hybrid nanogenerator (PT-HNG). Based on the working mechanism of a freestanding triboelectric nanogenerator (TENG), the PT-HNG can directly convert pressure stimuli into electrical energy and triboelectrification-induced electroluminescence (TIEL) signals. It achieves luminescence brightness of 0.06 mW cm−2 (3.84 cd m−2) and simultaneously delivers excellent electrical output performance (172.4 V, 6.36 μA, 43.7 nC) under sliding motion. More importantly, compatible with existing industrial papermaking processes, the PT-HNG is scalable for large-scale production. By combining PT-HNG with deep learning algorithms, a handwritten e-book system based on trajectory recognition was constructed, with a recognition accuracy of up to 95.5%. In addition, real-time intelligent control of PowerPoint presentations via PT-HNG was demonstrated. This study provides a new pathway for converting wastepaper into intelligent products and presents a novel idea for the interdisciplinary integration of the circular economy and advanced electronic technology.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5040023

Authors: Ashraf E. Abdel-Ghany Somia M. Abbas Ahmed M. Hashem Alain Mauger Christian M. Julien

This work deals with the comparative analysis of fluoride coatings, i.e., 5 wt.% AlF3 and LiF, applied as surface layer of Li-rich Li1.2Ni0.13Co0.13Mn0.54O2 (LNCM) layered oxides synthesized via facile and cost-effective sol–gel route. The detailed structural and morphological characterizations demonstrate that AlF3 and LiF deposits have a pivotal role in enhancing the electrochemical properties of LNCM. These electrochemical properties include galvanostatic charge–discharge (GCD), differential capacity (dQ/dV), electrochemical impedance spectroscopy (EIS), and area-specific impedance (ASI). A much lower decay of the discharge capacity of 0.22 and 0.25 mAh g−1 per cycle was obtained for AlF3- and LiF-coated LMNC, respectively, after 100 charge/discharge cycles at 0.1 C compared with 0.42 mAh g−1 per cycle for pristine LNCM. Results evidence the non-evolution of the charge transfer resistance, enhanced lithium-ion kinetics and stabilization of electrode/electrolyte interface during cycling.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5040022

Authors: Vanderley F. Gomes Junior Danilo A. Oliveira Paulo V. Morais José R. Siqueira Junior

Tungsten oxide (WO3) nanostructures have emerged as promising electroactive materials due to their high pseudocapacitance, structural versatility, and chemical stability, while reduced graphene oxide (rGO) provides excellent electrical conductivity and surface area. The strategic combination of these nanomaterials in hybrid electrodes has gained attention for enhancing the energy storage performance of supercapacitors. In this work, we report the fabrication and electrochemical performance of nanostructured multilayer films based on the electrostatic Layer-by-Layer (LbL) self-assembly of poly (amidoamine) (PAMAM) dendrimers alternated with tungsten oxide (WO3) nanofibers dispersed in reduced graphene oxide (rGO). The films were deposited onto indium tin oxide (ITO) substrates and subsequently subjected to electrochemical reduction. UV-Vis spectroscopy confirmed the linear growth of the multilayers, while atomic force microscopy (AFM) revealed homogeneous surface morphology and thickness control. Electrochemical characterization by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) revealed a predominantly electrical double-layer capacitive (EDLC) behavior. From the GCD measurements (PAMAM/rGO-WO3)20 films achieved an areal capacitance of ≈2.20 mF·cm−2, delivering an areal energy density of ≈0.17 µWh·cm−2 and an areal power density of ≈2.10 µW·cm−2, demonstrating efficient charge storage in an ultrathin electrode architecture. These results show that the synergistic integration of PAMAM dendrimers, reduced graphene oxide, and WO3 nanofibers yields a promising strategy for designing high-performance electrode materials for next-generation supercapacitors.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5040021

Authors: Ya Yang

The advancement of sensor systems that facilitate our daily lives relies on small, disposable batteries, which contribute to environmental pollution [...]

Nanoenergy Advances doi: 10.3390/nanoenergyadv5040020

Authors: Mahshid Mokhtarnejad Erick L. Ribeiro Karen Y. Patino Jaimes Mariana Milano-Benitez Bamin Khomami

This study introduces a modified Laser Ablation Synthesis in Solution (LASiS), a surfactant-free and rapid synthesis approach that enables uniform MOF nucleation on graphene oxide (GO) and precise control over crystallinity, for fabricating graphene oxide (GO)-integrated cobalt-based ZIF-67 hybrid nanocomposites tailored for supercapacitor applications. By tuning LASiS parameters, we precisely controlled framework size, morphology, and crystallinity, enabling sustainable and scalable production. The incorporation of GO during synthesis markedly enhances the uniform dispersion of ZIF-67 frameworks, minimizing aggregation and establishing interconnected conductive pathways via strong π-π stacking interactions. Following thermal reduction at 250 °C, the Co/ZIF-67–rGO composites exhibit outstanding electrochemical performance, achieving a specific capacitance of 1152 Fg−1 at 1 Ag−1 in a three-electrode configuration, driven by the synergistic combination of pseudocapacitive cobalt centers and double-layer capacitance from rGO. Structural analyses confirm the preservation of ZIF crystallinity and robust interfacial integration with the graphene sheets. Embedding these nanocomposites into fully 3D-printed supercapacitors yields a specific capacitance of 875 Fg−1, demonstrating their suitability for additive manufacturing despite minor increases in interfacial resistance. The 3D-printed supercapacitor devices delivered an energy density of 77.7 Wh/kg at a power density of 399.6 W/kg. Collectively, these results highlight the potential of LASiS-engineered MOF-based nanocomposites as scalable, high-performance materials for next-generation energy storage devices.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5040019

Authors: Vikram Lakshmi Suneetha Velpula Mahesh Khanapuram Uday Kumar Rajaboina Rakesh Kumar

The increasing accumulation of medical waste, especially discarded pharmaceutical blister packs, poses both environmental risks and missed opportunities for resource recovery. In this work, we demonstrate, for the first time, the direct upcycling of tablet blister waste into a potential frictional layer in triboelectric nanogenerators (TENGs). The polymer structure of blister packs, combined with Silicone rubber as a counter frictional layer, enabled the fabrication of durable TENG devices (TS-TENGs). Systematic electrical testing revealed that the TS-TENG achieved an open-circuit voltage of approximately 300 V, a short-circuit current of about 40 μA, and a peak power density of 3.54 W/m2 at an optimal load resistance of 4 MΩ. The devices maintained excellent stability over 10,000 mechanical cycles, confirming their durability. Practical demonstrations included powering 240 LEDs, four LED lamps, and portable electronic devices, such as calculators and hygrometers, through capacitor charging. This study shows that not only can tablet blister waste be used as a triboelectric material but it also presents a sustainable method to reduce pharmaceutical waste while advancing self-powered systems. The approach offers a scalable and low-cost means to integrate medical waste management with renewable energy technologies.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5040018

Authors: Ataur Rahman Md Mohamad Qatu Labib Hasan Rafia Afroz Mehdi Ghatus Sany Ihsan

Electrolysis and biological processes, such as fermentation and microbial electrolysis cells, offer efficient hydrogen production alongside wastewater treatment. This study presents a novel microbial electrolyzer (ME) comprising a titanium dioxide (TiO2) anode, a nickel–iron–carbon (NiFeC) cathode, and a cellulose nanocrystal proton exchange membrane (CNC-PEM) designed to generate hydrogen from palm oil mill effluent (POME). The system is powered by a 12 V electric double-layer organic supercapacitor (EDLOSC) integrated with a ZnO/PVA-based solar thin film. Power delivery to the TiO2-NiFeC-PEM electrolyzer is optimized using an Adaptive Neuro-Fuzzy Inference System (ANFIS). Laboratory-scale pilot tests demonstrated effective degradation of POME’s organic content, achieving a hydrogen yield of approximately 60%. Additionally, the nano-structured ZnO/CuO–ZnO/PVA solar film facilitated stable power supply, enhancing in situ hydrogen production. These results highlight the potential of the EDLOSC-encased ZnO/PVA-powered electrolyzer as a sustainable solution for hydrogen generation and industrial wastewater treatment.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5040017

Authors: Lang Yao Yanzhi Yang Sirong Li Xuechun Xiao

In this paper, spherical-shaped catalytic materials with needle-like stacking structures were synthesized in situ on the foam nickel substrate using the hydrothermal method, resulting in the NiM (M = Co, Mn, W, Zn)-MOF series. Furthermore, the catalyst with the best performance was obtained by adjusting the ratio of metal elements. Electrochemical tests show that NiCo-MOF (Ni: Co = 1:2) has the best electrocatalytic performance. During the UOR process, NiCo-MOF exhibits the optimal performance in 1 M KOH and 0.5 M urea solution, with a potential of only 1.33 V at a current density of 10 mA/cm2. The improvement in the activity of NiCo-MOF can be attributed to the synergistic effect between the Ni and Co bimetals, which leads to an increase in the electron transfer rate, the exposure of active sites, and an improvement in conductivity. Moreover, metal–organic framework materials are widely used as electrocatalysts due to their compositional diversity, rich pore structures, and high specific surface areas. Meanwhile, NiCo-MOF was used as a UOR and HER catalyst to assist the overall water decomposition with urea, and it showed relatively excellent performance. Only a voltage of 1.56 V was required to drive the current density of 10 mA/cm2 of the UOR || HER system. Therefore, the synthesized NiCo-MOF catalyst plays an important role in improving the efficiency of hydrogen production from water electrolysis and has promising sustainable application prospects.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5040016

Authors: Yibing Ma Jianye Gao Yiyue Tao Chen Hua Tangzhen Guan Cai Cheng Yujia Song Jing Liu

The pursuit of advanced energy technologies has intensified the focus on innovative functional materials. Low-melting-point liquid metals (LMs), particularly Ga-based alloys, have emerged as a promising platform due to their unique combination of metallic conductivity, fluidity, and biocompatibility. Nanoscaling LMs to create nano-liquid metals (nano-LMs) further unlocks extraordinary properties, including electrical duality, enhanced surface reactivity, tunable plasmonics, and remarkable deformability, surpassing the limitations of their bulk counterparts. This review provides a comprehensive overview of the recent progress in nano-LM-based energy technology. We begin by delineating the fundamental properties of LMs and the novel characteristics imparted at the nanoscale. Subsequently, we critically analyze mainstream synthesis strategies, such as sonication, mechanical shearing, and microfluidics. The core of the review focuses on innovative applications in energy storage devices, energy harvesting system, and catalysis for energy conversion. Finally, we discuss persistent challenges in stability, scalable synthesis, and mechanistic understanding, while offering perspectives on future research directions aimed at realizing the full potential of nano-LMs in next-generation intelligent and sustainable energy systems.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5040015

Authors: Shuyao Li Yuxuan Lai Zujian Gong Huangxuan Zhang

Real-time monitoring of lubricants is crucial to the development of transport vehicles. Accidental and fatal failures of components in vehicles occur every day, which threaten the service life of equipment. Inspired by the work of solid–liquid triboelectric nanogenerators (S-L-TENG), we propose a method to retrofit a self-powered sensor for real-time monitoring of lubricating oil leakage. The previous work does not have a systematic study on the influence of various modification methods on the electrification signal of oil-solid contact. This study identifies an optimal modification method with the highest electrification performance by comparing the energizing signals of different modification methods, which provides a new approach for the real-time monitoring of lubricating oil leakage and the detection of lubricating oil impurities.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5040014

Authors: Xue Bai Jian Chen Shengxi Du Yan Xiong

Titanium dioxide (TiO2) is widely used in solar cells and photocatalysts, given its excellent photoactivity, low cost, and high structural, electronic, and optical stability. Here, a novel TiO2 composite was prepared by coating TiO2 inverse opal (IO) with TiO2 nanorods (NRs). With a porous three-dimensional network structure, the composite exhibited higher light absorption; enhanced the separation of the electron–hole pairs; deepened the infiltration of the electrolyte; better transported and collected charge carriers; and greatly improved the power conversion efficiency (PCE) of the quantum-dot sensitized solar cells (QDSSCs) based on it, while also boosting its own photocatalytic hydrogen generation efficiency. A very high PCE of 12.24% was achieved by QDSSCs utilizing CdS/CdSe sensitizer. Furthermore, the TiO2 composite exhibited high photocatalytic activity with a H2 release rate of 1080.2 μ mol h−1 g−1, several times that of bare TiO2 IO or TiO2 NRs.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5040013

Authors: Balaraman Vedhanarayanan Jagadesh Nagaraj Kishorekumar Arjunan K. C. Seetha Lakshmi

The increasing demand for sustainable and high-performance energy storage underscores the limitations of lithium-ion batteries (LIBs), notably in terms of finite resources, safety issues, and rising costs. Multivalent metal-ion batteries (MMIBs)—employing Zn2+, Mg2+, Ca2+, and Al3+ ions—represent promising alternatives, as their multivalent charge carriers facilitate higher energy densities and greater electron transfer per ion. The widespread availability, lower cost, and favorable safety profiles of these metals further enhance MMIB suitability for large-scale deployment. However, MMIBs encounter significant obstacles, including slow ion diffusion, strong Coulombic interactions, electrolyte instability, and challenging interfacial compatibility. This review provides a systematic overview of recent advancements in MMIB research. Key developments are discussed for each system: electrode synthesis and flexible architectures for zinc-ion batteries; anode and cathode innovation alongside electrolyte optimization for magnesium-ion systems; improvements in anode engineering and solvation strategies for calcium-ion batteries; and progress in electrolyte formulation and cathode design for aluminum-ion batteries. The review concludes by identifying persistent challenges and future directions, with particular attention to material innovation, electrolyte chemistry, interfacial engineering, and the adoption of data-driven approaches, thereby informing the advancement of next-generation MMIB technologies.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5040012

Authors: Rouyi Lu Yinuo Wang Hao Pang Panpan Zhang Qilin Hua

Intrinsically stretchable polymer ionic conductors (PICs) hold significant application prospects in fields such as flexible sensors, energy storage devices, and wearable electronic devices, serving as promising solutions to prevent mechanical failure in flexible electronics. However, the development of PICs is hindered by an inherent trade-off between mechanical robust and electrical properties. Cellulose, renowned for its high mechanical strength, tunable chemical groups, abundant resources, excellent biocompatibility, and remarkable recyclability and biodegradability, offers a powerful strategy to decouple and enhance mechanical and electrical properties. This review presents recent advances in cellulose-based polymer ionic conductors (CPICs), which exhibit exceptional design versatility for flexible electrodes and strain sensors. We systematically discuss optimization strategies to improve their mechanical properties, electrical conductivity, and environmental stability while analyzing the key factors such as sensitivity, gauge factor, strain range, response time, and cyclic stability, where strain sensing refers to a technique that converts tiny deformations (i.e., strain) of materials or structures under external forces into measurable physical signals (e.g., electrical signals) for real-time monitoring of their deformation degree or stress state.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5030011

Authors: Sami Ur Rahman Shehna Farooq Narasimharao Kitchamsetti Muhammad Sajid Salma Gul Fahad Farooq Muhammad Rafiq Irum Fatima Humaira Razzaq

Polyaniline (PANI) nanofibers (NFs) were synthesized via two chemical oxidative polymerization approaches: a rapid mixing process and a conventional stirred tank method. PANI is a promising electrode material for supercapacitors due to its conductivity, stability, and pseudocapacitive redox behavior. The rapid mixing route proved especially effective, as fast polymerization promoted homogeneous nucleation and yielded thin, uniform, and interconnected NFs, whereas conventional stirring produced thicker, irregular fibers through heterogeneous nucleation. Structural characterization (FTIR, UV-Vis, XRD, XPS, TGA) confirmed that both samples retained the typical emeraldine form of PANI, but morphological analyses (SEM, BET) revealed that only the rapid process preserved nanofiber uniformity and porosity. This morphological control proved decisive for electrochemical behavior: symmetric supercapacitor devices fabricated from rapidly synthesized NFs delivered higher specific capacitances (378.8 F g−1 at 1 A g−1), improved rate capability, and superior cycling stability (90.33% retention after 3000 cycles) compared to devices based on conventionally prepared NFs. These findings demonstrate that rapid polymerization offers a simple and scalable route to morphology-engineered PANI electrodes with enhanced performance.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5030010

Authors: Morgana Rosset Yan Resing Dias Liliana Amaral Féris Oscar William Perez-Lopez

The catalytic decomposition of CH4 is a promising method for producing high-purity COx-free hydrogen. A Ni-Al-LDH catalyst synthesized via coprecipitation was modified with alkali metals (Mg, La, Ca, or Li) through reconstruction to enhance catalytic activity and resistance to deactivation during catalytic methane decomposition (CMD). The catalysts were evaluated by two activation methods: H2 reduction and direct heating with CH4. The MgNA-R catalyst achieved the highest CH4 conversion (65%) at 600 °C when reduced with H2, attributed to a stronger Ni-Al interaction. Under CH4 activation, LaNA-C achieved a 55% conversion at the same temperature, associated with a smaller crystallite size and higher reducibility due to La incorporation. Although all catalysts deactivated due to carbon deposition and/or sintering, LaNA-C was the only sample that could resist deactivation for a longer period, as La appears to have a protective effect on the active phase. Post-reaction characterizations revealed the formation of graphitic and filamentous carbon. Raman spectroscopy exhibited a higher degree of graphitization and structural order in LaNA-C, whereas SEM showed a more uniform distribution of carbon filaments. TEM confirmed the presence of multi-walled carbon nanotubes with encapsulated Ni particles in La-promoted samples. These results demonstrate that La addition improves the catalytic performance under CH4 activation and carbon structure. This finding offers a practical advantage for CMD processes, as it reduces or eliminates the need to use hydrogen during catalyst activation.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5030009

Authors: Talia Tene Orkhan Gulahmadov Lala Gahramanli Mustafa Muradov Jadranka Blazhevska Gilev Telli Hamzayeva Shafag Bayramova Stefano Bellucci Cristian Vacacela Gomez

This work reports the fabrication and optimization of nylon/multi-walled carbon nanotube (MWCNT) nanocomposite-based triboelectric nanogenerators (TENGs) using a spin coating method. By carefully tuning the MWCNT concentration, the device achieved a substantial enhancement in electrical output, with open-circuit voltage and short-circuit current peaking at 29.7 V and 3.0 μA, respectively, at 0.05 wt% MWCNT loading on the surface of nylon. The corresponding power density reached approximately 13.9 mW/m2, representing a significant improvement over pure nylon-based TENGs. The enhanced performance is attributed to improved charge trapping and dielectric properties due to well-dispersed MWCNTs on the surface of nylon, while excessive loading caused agglomeration, reducing efficiency. This lightweight, flexible nanocomposite TENG offers a promising solution for efficient, sustainable energy harvesting in wearable electronics and self-powered sensor systems, highlighting its potential for practical energy applications.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5020008

Authors: Jie Wang Fan He Min Zhang

The recent focus on wide-bandgap absorbers for tandem solar cell configurations and photovoltaic materials with high absorption coefficients for indoor photovoltaics has prompted a renewed interest in selenium. Over the past few years, the efficiency of Se solar cells has improved significantly, bringing the prospect of industrial production closer to reality. This study presents an innovative vapor transport deposition (VTD) technique for the scalable and cost-effective fabrication of Se thin films. The prepared Se thin films were characterized, and the results show that the VTD method is capable of producing dense and well-crystallized Se thin films. Se solar cells with a structure of glass/FTO/TiO2/Se/Au were fabricated to evaluate the impact of substrate temperature on device performance. The optimal performance was achieved on the hot side of the substrate during deposition, with a power conversion efficiency (PCE) of 2.56%. This study provides a promising pathway for the low-cost, high-throughput manufacturing of high-performance Se solar cells, facilitating their potential industrial implementation.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5020007

Authors: Suany E. Vázquez-Valdés Primavera Argüelles-Lucho Rosa M. Woo-García Edith Osorio-de-la-Rosa Francisco López-Huerta Agustín L. Herrera-May

The technological advances in internet of things (IoT) devices have raised the demand for cost-efficient and sustainable energy sources. Piezoelectric energy harvesters (PEHs) are promising low-cost and eco-friendly energy sources but require robust power management circuits (PMCs) for voltage conversion and regulation. This work presents a complementary metal–oxide–semiconductor (CMOS)-based PMC, integrating a reconfigurable AC-DC rectifier and a low-dropout (LDO) voltage regulator designed using 0.18 µm Taiwan semiconductor manufacturing company (TSMC) CMOS technology. This design includes an intermediate coupling stage to reduce voltage drop and improve the transfer efficiency of the PMC. In addition, we develop numerical simulations of the PMC performance, achieving a voltage conversion efficiency (VCE) between 72.8% and 43.21% using input voltages from 0.7 V to 2.8 V with a 50 kΩ load resistance. Compared to previous designs, the proposed circuit demonstrates improved stability, reduced area (66.28 mm2), and extended operating voltage range, allowing its potential application for ultra-low-power IoT nodes. This PMC contributes to the development of autonomous systems with reduced battery dependency and enhanced sustainability.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5020006

Authors: Carlos A. Castilla-Martinez Perla C. Meléndez-González Umit B. Demirci

Borocarbonitrides (BCNs), a new class of ternary materials combining boron, carbon, and nitrogen atoms, have emerged as promising candidates in decarbonization technologies due to their unique physicochemical properties. BCNs offer an adjustable atom composition and electronic structure, thermal stability, and potentially a large specific surface area, which are attractive features for efficient interactions with carbon dioxide. These make BCNs suitable for carbon dioxide capture, storage, and catalytic conversion applications. Furthermore, BCNs have the potential to (electro)catalyze the synthesis of green fuels, such as hydrogen, as well as that of other hydrogen carriers such as ammonia. With this review, we examine the recent advances in BCN synthesis methods, characterization, and functional applications while focusing on their role in the decarbonization technologies mentioned above. We aim to highlight the potential of BCNs to drive innovation in sustainable carbon management. Additionally, in the last section of this paper, we discuss the challenges and prospects of BCNs in decarbonization and beyond.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5020005

Authors: Syedvali Pinjari Tapan Bera Erik Kjeang

In this work, zeolitic imidazolate frameworks (ZIF-8, ZIF-67, and ZC-ZIF) and their hybrid composites with carboxylate-functionalized carbon nanotubes (fCNTs) are synthesized through low-cost synthesis methods for enhanced physisorption-based hydrogen storage at room temperature. While both base and hybrid structures are designed to improve hydrogen uptake, the base materials exhibit the most notable performance compared to their carbon hybrid counterparts. The structural analysis confirms that all samples maintain high crystallinity and exhibit well-defined rhombic dodecahedral morphologies. The hybrid composites, due to the intercalation of fCNTs, show slightly larger particle sizes than their base materials. X-ray photoelectron spectroscopy reveals strong nitrogen–metal coordination in the ZIF structures, contributing to a larger specific surface area (SSA) and optimal microporous properties. A linear fit of SSA and hydrogen uptake indicates improved hydrogen transport at low pressures due to fCNT addition. ZIF-8 achieves the highest SSA of 2023.6 m2/g and hydrogen uptake of 1.01 wt. % at 298 K and 100 bar, with 100% reversible adsorption. Additionally, ZIF-8 exhibits excellent cyclic repeatability, with only 10% capacity reduction after five adsorption/desorption cycles. Kinetic analysis reveals that hydrogen adsorption in the ZIF materials is governed by a combination of surface adsorption, intraparticle diffusion, and complex pore filling. These findings underscore the potential of ZIFs as superior materials for room-temperature hydrogen storage.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5020004

Authors: Massimo Mariello

Nowadays, due to improvements in living standards, more attention is reserved to all-around disease prevention and health care. In particular, research efforts have been made for developing novel methods and treatments for anti-cancer therapy. Self-powered nanogenerators have emerged in recent years as an attractive cost-effective technology to harvest energy or for biosensing applications. Bioelectronic nanogenerators can be used for inducing tissue recovery and for treating human illness through electrical stimulation. However, there is still a lack of comprehensive cognitive assessment of these devices and platforms, especially regarding which requirements must be satisfied and which working principles for energy transduction can be adopted effectively in the body. This review covers the most recent advances in bioelectronic nanogenerators for anti-cancer therapy, based on different transducing strategies (photodynamic therapy, drug delivery, electrical stimulation, atomic nanogenerators, etc.), and the potential mechanisms for tissue repair promotion are discussed. The prospective challenges are finally summarized with an indication of a future outlook.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5010003

Authors: Ioannis T. Papadas Sergey M. Pozov Iain Hamilton Marc Sims Ioannis Vamvasakis Apostolos Ioakeimidis Gerasimos S. Armatas Donal D. C. Bradley Stelios A. Choulis

In this paper, we present a one-step low-temperature solution combustion synthesis (SCS) of CuS nanoparticulated functional films processed via a simple blade-coating technique. This SCS route uses thiourea as a fuel and sulfur source, combined with copper(II) nitrate as an oxidant and a cupric ion source in an aprotic solvent such as non-toxic DMSO. It is hereby shown that the proposed SCS process formed a stable and completely dissolved molecular ink of thiourea and copper ion complexes, crucial for obtaining the pure crystalline phase of CuS nanoparticles (NPs). The CuS was formed by calcination at a low temperature of 200 °C during a brief annealing time of 20 min, to promote the synthesis of ~10 nm CuS NPs. The obtained CuS NPs were thoroughly analyzed in terms of structure and optoelectronic properties using various analytic and spectroscopic techniques, including TGA, XRD, FE-SEM, EDS, AFM, and four-point probe electrical resistivity measurements. The functionality of the prepared CuS nanoparticulated interlayers was evaluated by incorporating them as a hole injection layer (HIL) in Super Yellow (SY) organic light-emitting diodes (OLEDs).

Nanoenergy Advances doi: 10.3390/nanoenergyadv5010002

Authors: Zhangsiyuan Jin Hening Xing Yian Hu Yuljae Cho

Research on triboelectric nanogenerators (TENGs) and self-powered devices has rapidly grown in recent years since its first report in 2012 by Prof. Wang’s group. Triboelectric polymers have been a frontier of the research, attributed to their high surface potential and consequently high voltage output. To further advance the field, in recent years, photoactive semiconductor materials have been introduced which offer an additional current generation mechanism under light excitation, boosting the output current of the TENG. In addition, the semiconductor-based TENG further provides an ability to detect photo-signals beyond mechanical signals, adding high value towards advanced multi-functional sensor applications. In this regard, this article aims to review the recent progress in semiconductor-based TENGs, particularly on metal-halide perovskites, and their applications to self-powered electronics. Finally, the prospects and challenges of the perovskite-based TENG are discussed.

Nanoenergy Advances doi: 10.3390/nanoenergyadv5010001

Authors: Giulio Fatti Hyunseok Ko Sung Beom Cho

Understanding the mechanism underlying triboelectrification (TE) in polymers is crucial for developing cheap and effective triboelectric nanogenerators. Finding out how a polymer becomes tribopositive is especially relevant, as most polymers tend to charge negatively, reducing the power output and the range of applications. Thus far, it has remained unclear whether TE in polymers is to be attributed to homolytic ion transfer, heterolytic material transfer, or electronic transfer. Investigating the triboelectrification mechanism of polyoxymethylene by first-principle investigations, this study reveals a novel pathway driven by homolytic bond rupture. Our study demonstrates that the homolytic cleavage of a C–H bond upon contact with a metal surface drives a rearrangement in the oxidation state of the carbon atom, leading its dangling bond to cede an electron to the countersurface, leading to significant positive charging of the POM. This mechanism aligns with the triboelectric series and experimental observations. These insights suggest that TE mechanisms can be more complicated than heterolytic material transfer, depending on material-specific composition and chemistry. This study potentially paves the way for designing materials with tailored triboelectric properties for enhanced nanogenerator performance.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4040023

Authors: Huiyun Zhang Zhengfeng Liu Xinkai Xie Jun Wu Qiongfeng Shi

With the rapid advancement of the Internet of Things (IoT) era, the demand for wireless sensing and communication is increasingly prominent. Tens of thousands of sensing and communication nodes have presented new challenges to distributed energy. As a green energy harvesting technology, the triboelectric nanogenerator (TENG), with its outstanding characteristics of simple configuration, low cost, and high compatibility, demonstrates significant advantages in self-powered sensing systems and great application potential in the fields of human–machine interaction and wearable devices in the IoT era. More importantly, the electric displacement field and modulated electromagnetic waves that TENG triggers have opened a new paradigm for self-powered wireless communication, making up for the disadvantages of power supply by traditional distributed power sources. This review comprehensively discusses the latest scientific and technological progress in wireless communication technology prompted by TENG and further discusses its potential applications in various promising fields. Finally, a summary and outlook of TENG-based self-powered sensing and wireless communication synergic systems are presented, aiming to stimulate future innovation in the field and accelerating the paradigm shift to a fully self-powered IoT era.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4040022

Authors: Qicheng Ding Aamir Rasheed Haonan Zhang Sara Ajmal Ghulam Dastgeer Kamoladdin Saidov Olim Ruzimuradov Shavkat Mamatkulov Wen He Peihong Wang

This work presents the fabrication of a coaxial fiber triboelectric sensor (CFTES) designed for efficient energy harvesting and gesture detection in wearable electronics. The CFTES was fabricated using a facile one-step wet-spinning approach, with PVDF-HFP/CNTs/Carbon black as the conductive electrode and PVDF-HFP/MoS2 as the triboelectric layer. The incorporation of 1T phase MoS2 into the PVDF-HFP matrix significantly improves the sensor’s output owing to its electron capture capabilities. The sensor’s performance was carefully optimized by varying the weight percentage of MoS2, the thickness of the fiber core, and the CNT ratio. The optimized CFTES, with a core thickness of 156 µm and 0.6 wt% MoS2, achieved a stable output voltage of ~8.2 V at a frequency of 4 Hz and 10 N applied force, exhibiting remarkable robustness over 3600 s. Furthermore, the CFTES effectively detects human finger gestures, with machine learning algorithms further enhancing its accuracy. This innovative sensor offers a sustainable solution for energy transformation and has promising applications in smart portable power sources and wearable electronic devices.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4040021

Authors: Ziling Song Xianfa Cai Zhi Chen Ziying Zhu Yunqi Cao Wei Li

Ferroelectret nanogenerators (FENGs) have garnered attention due to their unique porous structure and excellent piezoelectric performance. However, most existing FENGs lack sufficient stretchability and flexibility, limiting their application in the field of wearable electronics. In this regard, we have focused on the development of an ultrathin, stretchable, and twistable ferroelectret nanogenerator (UST-FENG) based on Ecoflex, which is made up of graphene, Ecoflex, and anhydrous ethanol, with controllable pore shape and density. The UST-FENG has a thickness of only 860 µm, a fracture elongation rate of up to 574%, and a Young’s modulus of only 0.2 MPa, exhibiting outstanding thinness and excellent stretchability. Its quasi-static piezoelectric coefficient is approximately 38 pC/N. Utilizing this UST-FENG device can enable the recognition of facial muscle movements such as blinking and speaking, thereby helping to monitor people’s facial conditions and improve their quality of life. The successful application of the UST-FENG in facial muscle recognition represents an important step forward in the field of wearable systems for the human face.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4040020

Authors: Masoumeh Karimi Kisomi Muhammad Sohaib Roomi M. A. Parvez Mahmud

Triboelectric nanogenerators (TENGs) are a promising technique for harvesting environmental energy that is based on electrostatic induction and contact electrification. This is a method that uses every relative motion between two electrodes to convert mechanical energy into electrical energy. Several modes of TENGs are designed based on various relative motions between electrode pairs. As TENGs are a surface phenomenon, properties such as the structure of the electrodes are key parameters that affect their performance. In this paper, in order to identify the best pattern designed adapted to the TENG mode, the effect of surface structures in each mode is investigated numerically. To achieve the best performance of the micro-patterned electrode, a comparative study has been conducted on the four TENG modes under the same conditions. To reach this goal, micro-patterned shapes such as pyramid, spherical, and cube structures are designed, and the open circuit voltage is calculated and compared to a flat surface. The results show that surface modification has a significant role in TENG’s performance. Based on this study, by using a cube-patterned electrode instead of a flat electrode, the output voltage increases from 233 V to 384 V in sliding mode. Also, by applying the spherical pattern, the output voltage is 1.7 times higher than a flat electrode in contact-separation mode. In the case of investigating TENG pattern structure, the results show that the electrical outputs of the patterned layer depend on the mode. The spherical pattern has a higher impact in contact-separation mode compared to the cube pattern. Meanwhile, in sliding mode, the cube pattern has a greater effect. This work provides a hint for designing an effective pattern on electrodes for a particular mode to enhance TENG performance.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4040019

Authors: Olena Okhay Tao Yang Alexander Tkach

In a view of application of porous materials in wearable electronics and self-powered systems, reduced graphene oxide (rGO) foams modified by Mn or/and Bi were produced in this study to be used as electrodes for supercapacitors. The hydrothermal method and the freeze-drying processes were used for the preparation of the materials further morphologically, elementally and structurally analyzed. Based on the electrochemical characterization, Bi-modified rGO foam was found to be more a promising material for capacitive electrodes in comparison to the other prepared materials.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4040018

Authors: Tomasz Blachowicz Nonsikelelo Sheron Mpofu Andrea Ehrmann

Nanofibers can be produced by various techniques, such as a broad range of electrospinning techniques to produce nanofiber mats from different polymers or polymer blends, often filled with metallic or semiconducting nanoparticles or by different nanotechnological bottom-up or top-down methods. They are important parts of a wide variety of energy applications, such as batteries, fuel cells, photovoltaics, or hydrogen storage materials. Usually, their physical or chemical parameters are measured by averaging over a fiber bundle or a part of a nanofiber mat. Here, we report the possibility of measuring the different physical and chemical properties of single nanofibers and nanowires. Such measurements of single nanofiber properties are more complicated than investigations of fiber bundles or whole nanofiber mats and, thus, are less often found in the literature. After a fast increase in such investigations between 2001 and 2009, the numbers of respective studies are now stagnating. This review thus aims to make the different possibilities more visible to a broader scientific audience by providing several examples based on atomic force microscopy (AFM) and other broadly available techniques. The focus of this review is on technologies that reveal more information than the pure surface morphology of nanofibers or nanowires, such as mechanical properties or wettability, porosity, or electrical conductivity.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4030017

Authors: Zhen Pan Shunqi Yuan Yan Zhang Xi Ren Zhibin He Zhenzhong Wang Shujun Han Yuexin Qi Haifeng Yu Jingang Liu

As triboelectric nanogenerator (TENG) technology continue to evolve, its application in harsh environments has increasingly captivated the interest of researchers. However, the current research on heat-resistant triboelectric materials remains predominantly focused on the development of tribo-negative materials, with scant attention given to their equally crucial tribo-positive counterparts. In this study, the tribo-positive polyimide (PI) material with enhanced tribo-positivity is developed by integrating amide groups with electron-donating effects into the molecular chain. Furthermore, the TENG devices based on this series of tribo-positive PI materials have demonstrated an open-circuit voltage (VOC) of 242 V, a short-circuit current (ISC) of 8.13 μA, and a transferred charge (QSC) of 117 nC. Notably, these devices also demonstrate the capability to efficiently generate electricity even under elevated temperature conditions. This work not only proposes a potential molecular design strategy for developing high-performance tribo-positive PI materials applicable in TENGs, but also markedly propels the advancement of robust energy-harvesting devices engineered for operation at elevated temperatures.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4030016

Authors: Zhengbing Ding Xing Wang Chenyao Huang Kyungwho Choi Dukhyun Choi

In the realm of intelligent sports, the integration of triboelectric nanogenerators (TENGs) marks a transformative approach toward energy sustainability and more advanced athletic monitoring. By leveraging the principle of triboelectricity, TENGs ingeniously convert mechanical energy from athletes’ movements into electrical energy, which offers a green and efficient power solution for wearable technology. This paper presents an innovative study on the application of TENG technology in sports science, with the results illustrating the potential utility of TENGs in revolutionizing the way we monitor, analyze, and enhance athletic performance. Through the development of self-powered wearables and equipment, TENGs facilitate real-time data collection on physiological and biomechanical parameters, ultimately enabling personalized training adjustments and injury prevention strategies. Our findings underscore the dual benefit of TENGs in promoting environmental sustainability by reducing the overall reliance on traditional energy sources and growing the capabilities of intelligent sports systems. This research contributes to the burgeoning field of nano-energy sports applications while setting the stage for future explorations into the optimization of TENG integration in athletic performance enhancement. Finally, the paper concludes by discussing remaining challenges in this area and opportunities for further research.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4030015

Authors: Yukai Zhou Jia-Han Zhang Feiyu Wang Jiangbo Hua Wen Cheng Yi Shi Lijia Pan

The rise of the Internet of things has catalyzed extensive research in the realm of flexible wearable sensors. In comparison with conventional sensor power supply methods that are reliant on external sources, self-powered sensors offer notable advantages in wearable comfort, device structure, and functional expansion. The energy-harvesting modes dominated by piezoelectric nanogenerators (PENGs), triboelectric nanogenerators (TENGs), and pyroelectric nanogenerators (PyENGs) create more possibilities for flexible self-powered sensors. This paper meticulously examines the progress in flexible self-powered devices harnessing TENG, PENG, and PyENG technologies and highlights the evolution of these sensors concerning the material selection, pioneering manufacturing techniques, and device architecture. It also focuses on the research progress of sensors with composite power generation modes. By amalgamating pivotal discoveries and emerging trends, this review not only furnishes a comprehensive portrayal of the present landscape but also accentuates avenues for future research and the application of flexible self-powered sensor technology.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4030014

Authors: Marinos Tountas Katerina Anagnostou Evangelos Sotiropoulos Christos Polyzoidis Emmanuel Kymakis

In this study, we explored the potential of exfoliated transition metal dichalcogenides (TMDs) as innovative spray-coated hole transport layers (HTLs) in organic photovoltaics (OPVs), addressing the need for efficient and stable materials in solar cell technology. This research was motivated by the need for alternative HTLs that can offer enhanced performance under varying lighting conditions, particularly in indoor environments. Employing UV-visible absorption and Raman spectroscopy, we characterized the optical properties of MoS2, MoSe2, WS2, and WSe2, confirming their distinct excitonic transitions and direct bandgap features. The nanocrystalline nature of these TMDs, revealed through XRD patterns and crystallite size estimation using the Scherrer method, significantly contributes to their enhanced physical properties and operational efficiency as HTLs in OPVs. These TMDs were then integrated into OPV devices and evaluated under standard solar and indoor lighting conditions, to assess their effectiveness as HTLs. The results demonstrated that MoS2, in particular, displayed remarkable performance, rivalling traditional HTL materials like MoO3. It maintained high power conversion efficiency across a spectrum of light intensities, illustrating its versatility for both outdoor and indoor applications. Additionally, MoS2 showed superior stability over extended periods, suggesting its potential for long-term usage in OPVs. This study contributes significantly to the field of photovoltaic materials, presenting TMDs, especially MoS2, as promising candidates for efficient and stable OPVs in diverse lighting conditions, thereby broadening the scope of solar cell applications.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4030013

Authors: Renyun Zhang

Engineering polymers stand out as the predominant dielectric materials in triboelectric nanogenerators (TENGs), primarily owing to their robust triboelectric effect and widespread availability. However, growing environmental concerns surrounding these polymers have prompted a notable shift towards exploring alternative eco-friendly materials, with cellulose materials emerging as compelling contenders over the past few years. Cellulose, derived from various sources and presented in diverse forms and structures, has found utility as triboelectric materials. In contrast to many engineering polymers known for their chemical stability, cellulose materials exhibit heightened chemical activities. This characteristic provides a unique opportunity to delve into fundamental questions in TENGs by manipulating the physical and chemical properties of cellulose materials. This concise critical review aims to thoroughly examine the applications of cellulose materials while shedding light on the opportunities presented by these versatile materials.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4020012

Authors: Iuri Custodio Montes Candido Andre Luiz Freire Carlos Alberto Rodrigues Costa Helinando Pequeno de Oliveira

The development of more efficient friction layers for triboelectric nanogenerators is a complex task, requiring a careful balance of various material properties such as morphology, surface roughness, dielectric constant, and surface potential. In this study, we thoroughly investigated the use of cellulose acetate modified with different concentrations of zinc oxide and titanium dioxide to enhance energy harvesting for the TENG. The results indicate that the roughness degree is influenced by the homogeneous degree/aggregation level of doping agents in cellulose acetate membranes, leading to the best performance of open circuit voltage of 282.8 V, short-circuit current of 3.42 µA, and power density of 60 µW/cm2 for ZnO-doped cellulose acetate membranes.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4020011

Authors: Gudrun Wilhelm Ute Golla-Schindler Katharina Wöhrl Christian Geisbauer Graham Cooke Timo Bernthaler Hans-Georg Schweiger Gerhard Schneider

We examine the impact of water (160 ± 41 ppm of reference) on the anode, cathode, separator and electrolyte in two aging scenarios: calendric aging (60 °C, 80 days, charged state), resulting in a triggered current interrupt device (CID), and cycling 1680 times (charge/discharge with 1C, 2.75–4.2 V, 20 ± 2 °C), resulting in 24.5% residual capacity. We applied computer tomography (CT), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and secondary ion mass spectrometry (SIMS) to understand the capacity loss. The aged NMC/LCO–graphite cells were compared to a reference cell in pristine state. Both aging scenarios showed (a) thick depositions on the anode and cathode consisting mainly of oxygen, fluorine and phosphorous, (b) reduced separator pore sizes, (c) the deposition of Mn, Co and Ni on top of the anode and (d) the decomposition of the conductive salt LiPF6 accompanied by HF formation and a loss of active lithium. Calendric aging consumes the water content and additionally leads to (e) the decomposition of the organic solvent followed by CO2 gas formation. Cyclic aging increases the water content and additionally results in (f) the consumption of the additive fluoroethylene carbonate (FEC). These findings show how water affects aging phenomena and results in a capacity decrease in the cell.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4020010

Authors: Long Liu Tong Hu Xinmao Zhao Chengkuo Lee

This paper reviews and summarizes recent progress in blue energy harvesting based on a triboelectric nanogenerator (TENG). This review covers TENG-based blue energy harvesters (BEHs) with different inertial units in spherical structures, derivative spherical structures, buoy structures, and liquid–solid contact structures. These research works have paved the way for TENG-based BEHs working under low-frequency waves and harvesting wave energy efficiently. The TENG-based BEH unit design and networking strategy are also discussed, along with highlighted research works. The advantages and disadvantages of different TENG structures with other inertial units are explored and discussed. Meanwhile, power management strategies are also mentioned in this paper. Thus, as a promising blue energy harvesting technology, the TENG is expected to significantly contribute to developing low-cost, lightweight, and high-performance BEHs supporting more frequent marine activities.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4020009

Authors: Carlos Callaty Isabel Gonçalves Cátia Rodrigues João Ventura

Triboelectric nanogenerators (TENGs) are an attractive energy harvesting technology due to their high efficiency and vast applications in self-powered sensors. In this work, dielectric–dielectric contact-separation TENGs were modeled with time-dependent finite element simulations with the objective of improving TENG’s performance by enhancing the relative permittivity (εr).To achieve this, the chosen material (PDMS, εr=2.75) was doped with SrTiO3 (εr = 300) particles. The open-circuit voltage (VOC) and short-circuit current (ISC) remained constant as ϵr increased, as predicted by existent models, but in contradiction with available experimental data. Thus, we introduced a charge correction model relating ϵr and surface charge density, allowing us to observe an increase in TENG performance output (VOC and ISC). This work shows that finite element simulations are suitable for better understanding and optimizing TENGs’ performance.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4020008

Authors: Tanbir Kaur Sodhi Pascal Chrétien Quang Chieu Bui Amaury Chevillard Laurent Travers Martina Morassi Maria Tchernycheva Frédéric Houzé Noelle Gogneau

The optimization of the new generation of piezoelectric nanogenerators based on 1D nanostructures requires a fundamental understanding of the different physical mechanisms at play, especially those that become predominant at the nanoscale regime. One such phenomenon is the surface charge effect (SCE), which is very pronounced in GaN NWs with sub-100 nm diameters. With an advanced nano-characterization tool derived from AFM, the influence of SCE on the piezo generation capacity of GaN NWs is investigated by modifying their immediate environment. As-grown GaN NWs are analysed and compared to their post-treated counterparts featuring an Al2O3 shell. We establish that the output voltages systematically decrease by the Al2O3 shell. This phenomenon is directly related to the decrease of the surface trap density in the presence of Al2O3 and the corresponding reduction of the surface Fermi level pinning. This leads to a stronger screening of the piezoelectric charges by the free carriers. These experimental results demonstrate and confirm that the piezo-conversion capacity of GaN NWs is favoured by the presence of the surface charges.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4010007

Authors: Refilwe Edwin Mapasha Sentserere Phodisho Kgalema Hezekia Mapingire Emmanuel Igumbor

The possibility of using graphane monolayer crystals as an electrode material is becoming popular. Graphane is stable at room temperature and has a large surface area, but its chemical inertness hinders its direct interactions with Li ions. In this study, we performed density functional theory calculations to study the energetic stability and structural and electronic properties of Li on graphane with various CH divacancy configurations (v12, v13, and v14). The results show that the adsorption of the Li atom reduces the formation energy of the CH divacancy configurations. The Li-v12 is most stable with the highest binding energy of 3.25 eV/Li and relaxes to in-plane with other C atoms. Altering the Li charge state to have Li−1-v12 or Li+1-v12 affects the energetic stability and electronic characters of Li-v12. The Li−1-v12 (Li+1-v12) slightly (greatly) reduces the binding force between the Li and v12 configuration, and furthermore it improves (deteriorates) the conductivity of the structure. Further investigation of graphane with vacancies is encouraged due to these intriguing observations, as it holds promise for potential utilization as an electrode material.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4010006

Authors: Andre L. Freire Lais R. Lima Iuri C. M. Candido Luygui G. Silva Sidney J. L. Ribeiro Emanuel Carrilho Thais L. Oliveira Luiz Fernando C. de Oliveira Hernane S. Barud Helinando P. de Oliveira

Developing metal-free electrodes for prototypes of bio-based devices is an essential step in producing non-toxic components for implantable devices and wearables. In particular, the advancement in self-powered devices is a hot topic for several applications due to the possibility of creating free-battery devices and sensors. In this paper, the modification of bacterial cellulose by the progressive incorporation of carbon black (a conductive filler) was explored as a prototype for bio-based electrodes for triboelectric nanogenerators. This process was controlled by the percolation pathways’ activation through the contact of carbon black grains with the bacterial cellulose membrane, which represents a critical step in the overall process of optimization in the power output performance, reaching an open circuit voltage value of 102.3 V, short circuit current of 2 μA, and power density of 4.89 μW/cm2.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4010005

Authors: Yuanzheng Zhang Ju Chong Yiqian Mao Xiangyang Gao Jinmiao He Hao Wang Shishang Guo Haiwu Zheng

With the rapid evolution of the Internet of Things (IoT), smart home systems have greatly improved people’s lifestyles and quality of life. However, smart home systems based on a single sensor cannot efficiently control multiple terminals, which limits product penetration into lower-end markets. Here, we have developed a dual-mode smart home system based on a porous triboelectric nanogenerator (TENG), which effectively compensates for the shortcomings of smart home systems being unable to control multiple appliances through a single switch. Benefitting from the remarkable electronegativity of MXene and the ameliorative specific surface area of the friction layer, the output characteristics of the porous TENG are greatly improved. Under the identical external stimulus, the open-circuit voltage (VOC) and short-circuit current (ISC) of the porous TENG were 3.03 and 3.04 times higher than those of the TENG with a pure PVDF membrane used as the friction layer. Thanks to the excellent output performance and good linear relationship between pressure and voltage, the developed dual-mode smart home system could efficiently control multiple terminals through a single sensor. This work not only provides theoretical support for developing high-performance TENGs but also paves the way to designing multifunctional smart home systems.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4010004

Authors: Xianye Li Liang Xu Zhong Lin Wang

The utilization of abundant blue energy in the ocean could greatly contribute to achieving carbon neutrality. However, the unsolved economic and technical challenges of traditional technologies for harvesting blue energy have resulted in slow progress. Triboelectric nanogenerators (TENGs), as a new approach for converting mechanical energy into electricity, have great potential for blue energy harvesting, which can be connected as networks with different numbers of units for varying scales of energy harvesting. Here, recent advances of networking strategies of TENGs for harvesting blue energy are reviewed, mainly concerning mechanical and electrical connection designs. Anchoring strategies of devices and networks are also discussed. The development of TENG networks could provide an effective solution for large-scale ocean blue energy harvesting, which can also serve as an in-situ energy station or power source for self-powered systems, supporting various marine equipment and activities.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4010003

Authors: Baosen Zhang Yunchong Jiang Baojin Chen Haidong Li Yanchao Mao

Advances in biomimetic triboelectric nanogenerators (TENGs) have significant implications for electronic skin (e-skin) and human–machine interaction (HMI). Emphasizing the need to mimic complex functionalities of natural systems, particularly human skin, TENGs leverage triboelectricity and electrostatic induction to bridge the gap in traditional electronic devices’ responsiveness and adaptability. The exploration begins with an overview of TENGs’ operational principles and modes, transitioning into structural and material biomimicry inspired by plant and animal models, proteins, fibers, and hydrogels. Key applications in tactile sensing, motion sensing, and intelligent control within e-skins and HMI systems are highlighted, showcasing TENGs’ potential in revolutionizing wearable technologies and robotic systems. This review also addresses the challenges in performance enhancement, scalability, and system integration of TENGs. It points to future research directions, including optimizing energy conversion efficiency, discovering new materials, and employing micro-nanostructuring techniques for enhanced triboelectric charges and energy conversion. The scalability and cost-effectiveness of TENG production, pivotal for mainstream application, are discussed along with the need for versatile integration with various electronic systems. The review underlines the significance of making bioinspired TENGs more accessible and applicable in everyday technology, focusing on compatibility, user comfort, and durability. Conclusively, it underscores the role of bioinspired TENGs in advancing wearable technology and interactive systems, indicating a bright future for these innovations in practical applications.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4010002

Authors: Constantinos Moularas Aikaterini Gemenetzi Yiannis Deligiannakis Maria Louloudi

The utilization of plasmonic nanomaterials in catalytic technologies is an emerging research field with foreseeable applications in energy-catalytic technologies. On this front, the coupling of plasmonic nanomaterials with molecular catalysts is a newly approached, thus far unexploited field, that we discuss herein. In the present mini review, we contrast the case where the plasmonic particle itself is the catalytic center against the case where the plasmonic particle acts as a co-catalyst for an operational catalytic system. In the first part, we present an outline of the key phenomena in nanoplasmonics, and their potential implications in catalytic processes. The concepts of hot electrons, hot holes, and the dynamics of their generation and transfer are reviewed, as are the contribution of near-field and photothermal effects to catalytic processes. All these plasmonic-phenomena are then discussed in conjunction with representative catalytic systems from the literature.

Nanoenergy Advances doi: 10.3390/nanoenergyadv4010001

Authors: Weixin Dou Sihong Wang Rusen Yang

Future electronics will play a more critical role in people’s lives, as reflected in the realization of advanced human–machine interfaces, disease detection, medical treatment, and health monitoring. The current electronic products are rigid, non-degradable, and cannot repair themselves. Meanwhile, the human body is soft, dynamic, stretchable, degradable, and self-healing. Consequently, it is valuable to develop new electronic materials with skin-like properties that include stretchability, inhibition of invasive reactions, self-healing, long-term durability, and biodegradability. These demands have driven the development of a new generation of electronic materials with high-electrical performance and skin-like properties, among which e-polymers are increasingly being more extensively investigated. This review focuses on recent advances in synthesizing e-polymers and their applications in biointerfaces and organisms. Discussions include the synthesis and properties of e-polymers, the interrelationships between engineered material structures and human interfaces, and the application of implantable and wearable systems for sensors and energy harvesters. The final section summarizes the challenges and future opportunities in the evolving materials and biomedical research field.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3040020

Authors: Mingyan Xue Fangpei Li Wenbo Peng Quanzhe Zhu Yongning He

The coupling of pyroelectricity, semiconductor, and optical excitation yields the pyro-phototronic effect, which has been extensively utilized in photodetectors. It can also enhance the performance of light energy harvesting nanogenerators. In this work, a pyro-phototronic effect-enhanced MXene/ZnO heterojunction nanogenerator has been successfully demonstrated, which can harvest broadband light energy (from deep UV to near-infrared) and still operate at 200 °C. The morphology of the ZnO layer and the MXene layer’s thickness have been further optimized for better light energy harvesting performance. For the optimized heterojunction nanogenerator, the responsivity can be improved from ~0.2 mA/W to ~3.5 mA/W by pyro-phototronic effect, under 0.0974 mW/cm2 365 nm UV illumination. Moreover, the coupling of pyro-phototronic and piezo-phototronic effects in MXene/ZnO heterojunction nanogenerators has been investigated. The results indicate that only a small tensile strain could improve the nanogenerator’s performance. The working mechanisms have been carefully analyzed, and the modulation of piezoelectric charges on the Schottky barrier height is found to be the key factor. These results demonstrate the enormous potential of the pyro-phototronic effect in light energy harvesting nanogenerators and illustrate the coupling of pyro-phototronic and piezo-phototronic effects for further performance improvement.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3040019

Authors: Ananthakumar Soosaimanickam Alejandro Saura Noemi Farinós Rafael Abargues

The surface chemistry of cesium lead halide perovskite nanocrystals has been elaborately studied in recent years and has proved the critical role of carboxylic acids and amines in the formation and stability of the nanocrystals. Specifically, a slight change in the concentration and ratio of the frequently used oleic acid and oleylamine critically influences the resultant phase and physical properties. Thus, understanding the delicate surface of cesium lead halide perovskite nanocrystals mainly relies on chemical bonding and the dynamic ligand environment of these two organic species. In this aspect, this review summarizes experimental findings about the critical role of oleic acid and oleylamine on the nucleation, growth, stability, phase, and morphology of cesium lead halide perovskite nanocrystals and their effect under different circumstances.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3040018

Authors: Xiang Li Di Wei Zhong Lin Wang

With the global energy shortages, sustainable energy scavenging from the natural environment is desperately needed. Unlike solar cell or wind power, which depends heavily on weather conditions, triboelectric nanogenerator (TENG) has received extensive attention as an efficient all–weather energy–harvesting technology. Based on the coupling principle of contact electrification (CE) and electrostatic induction, conventional TENGs convert mechanical energy into an alternating current (AC) output. However, the typically distributed sensor systems in the ubiquitous Internet of Things (IoTs) request a direct current (DC) input. Direct current triboelectric nanogenerators (DC-TENGs) with the constant output characteristic are critical to satisfy the above requirements. Here, DC-TENGs were reviewed from the perspective of material selections. As device performance is mainly determined by material properties, the development of DC-TENGs could be divided into three categories based on dielectric materials, semiconductor materials, and materials for iontronic rectifications. The operating mechanism and influencing factors of various types of DC-TENG were summarized, representative applications were demonstrated, and the main challenges of future developments were also discussed.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3040017

Authors: Zhaosu Wang Ning Li Zhiyi Zhang Xiaojing Cui Hulin Zhang

Collecting ambient energy to power various wearable electronics is considered a prospective approach to addressing their energy consumption. Mechanical and thermal energies are abundantly available in the environment and can be efficiently converted into electricity based on different physical effects. Hydrogel-based energy harvesters have turned out to be a promising solution, owing to their unique properties including flexibility and biocompatibility. In this review, we provide a concise overview of the methods and achievements in hydrogel-based energy harvesters, including triboelectric nanogenerators, piezoelectric nanogenerators, and thermoelectric generators, demonstrating their applications in power generation, such as LED lighting and capacitor charging. Furthermore, we specifically focus on their applications in self-powered wearables, such as detecting human motion/respiration states, monitoring joint flexion, promoting wound healing, and recording temperature. In addition, we discuss the progress in the sensing applications of hydrogel-based self-powered electronics by hybridizing multiple energy conversion in the field of wearables. This review analyzes hydrogel-based energy harvesters and their applications in self-powered sensing for wearable devices, with the aim of stimulating ongoing advancements in the field of smart sensors and intelligent electronics.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3040016

Authors: Qianying Li Yi Xi

In recent years, the development of the Internet of Things has challenged traditional energy supply methods. Suddenly rising maintenance costs and serious environmental pollution have led to great concern over energy supply methods such as wired transmission and batteries. Fluid energy is a kind of clean energy widely existing in nature, which can effectively reduce costs and environmental pollution. In the field of collecting fluid energy, fluid energy converters based on triboelectric nanogenerators (FEC-TENGs) have always been a research hotspot. This paper reviews the latest research progress of FEC-TENGs. Firstly, the basic working principle and working mode of FEC-TENGs are introduced. Then, the theoretical process and application examples of converting fluid energy into electrical energy or electrical signals are analyzed in detail. According to the calculation process of energy conversion efficiency and the performance evaluation parameters, the structural design, performance output, and application fields of FEC-TENGs are summarized. Finally, this paper points out the challenges and shortcomings of the current FEC-TENGs and provides our views on the future development of this field.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3030015

Authors: Maoyi Zhang Liang Guo Jihai Hu Xingquan Wang Ya Yang Yewang Su

Backpack transportation is everywhere in daily life. Suspended-load backpacks (SUSBs) based on forced vibration have attracted lots of attention because of their ability to effectively reduce the cost on the body during motion. The smaller the natural frequency of SUSBs, the better the cost reduction. The natural frequency is determined by the elastic components of SUSBs. It is currently common to use rubber ropes and pulleys as elastic components. In the first part of this paper, we propose a pre-compression design for SUSBs, which has a simple structure and breaks through the limitation of rubber material. To make the natural frequency small enough, rubber ropes and compression springs require sufficient space. This leads to the current SUSBs being large and, therefore, not suitable for children to carry. Inspired by biology, here we propose a new design strategy of pre-rotation with pre-rotation spiral springs as elastic components. The pre-rotation design not only has the advantages of avoiding the inconvenience of material aging and the ability to adjust the downward sliding distance of the backpack but also greatly saves the space occupied by the elastic components, which can be adopted by small SUSBs. We have developed a theoretical model of the pre-rotation SUSBs and experimentally confirmed the performance of the pre-rotation SUSBs. This work provides a unique design approach for small SUSBs and small suspended-load devices. And the relative motion between the components inside the SUSB has a huge potential to be used by triboelectric nanogenerators for energy scavenging.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3030014

Authors: Maoyi Zhang Liang Guo Jihai Hu Xingquan Wang Ya Yang Yewang Su

Backpack transportation is commonly used in daily life. Reducing the cost of the backpack on the human body is a widely researched subject. Suspended-load backpacks (SUSBs) based on forced vibration can effectively reduce the cost during movement. The intrinsic frequency of the SUSB is determined by the elastic components of the SUSB. Previous researchers used pulleys and rubber ropes as the elastic components. We propose a pre-compression design strategy based on pre-compression springs. Compared with previous studies, the use of pre-compression springs as elastic elements improves the reliability of the SUSB structure, avoids the inconvenience of nonlinearity and material aging, and adds the ability to flexibly adjust the sliding distance of the backpack. Moreover, previous studies utilized the relative motion between the carrying part and the backpack part to scavenge the vibration energy. We propose that the vibration energy can also be scavenged by the relative motion between the elastic components. A theoretical model is developed for the pre-compression SUSB. We experimentally confirm the performance of the pre-compression SUSB. This work provides new design ideas for SUSBs with reduced energy costs. In Part 2, we propose a bio-inspired pre-rotation design that has the advantage of occupying less space.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3030013

Authors: Xin Cui Yaming Zhang Yan Zhang

Triboelectric nanogenerators (TENGs) are key technologies for the Internet of Things with energy harvesting. To improve energy conversion efficiency and convert mechanical energy into electrical energy, high charge density in TENGs plays a crucial role in the design of triboelectric materials and device structures. This paper proposes mechanisms and strategies to increase TENGs’ charge density through multi-charge storage layers. We also discuss the realization of higher charge densities through material and structure design. The implementation of novel charge storage strategies holds the potential for significant improvements in charge density.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3030012

Authors: Dongyang Fang Guangqin Gu Wenhe Zhang Guangxiang Gu Cong Wang Bao Zhang Gang Cheng Zuliang Du

As a new technology for harvesting distributed energy, the triboelectric nanogenerator (TENG) has been widely used in harvesting wind energy. However, the wind-driven TENG (WD-TENG) faces the problems of high frictional resistance and low mechanical energy conversion efficiency. Here, based on optimizing the structure of the wind turbine, a rotational double-electrode-layer WD-TENG (DEL-WD-TENG) is developed. When the rotational speed is less than 400 round per minute (rpm), the dielectric triboelectric layer rubs with the inner electrode layer under its gravity; when the rotational speed is higher than 400 rpm, the dielectric triboelectric layer rubs with the outer electrode layer under the centrifugal force. The double-electrode-layer structure avoids the energy loss caused by other forces except gravity, centrifugal, and electrostatic adsorption, which improves the mechanical energy conversion efficiency and prolongs the working life of the DEL-WD-TENG. The conversion efficiency from mechanical energy to electricity of the DEL-WD-TENG can reach 10.3%. After 7 million cycles, the transferred charge of the DEL-WD-TENG is reduced by about 5.0%, and the mass loss of dielectric triboelectric layer is only 5.6%. The DEL-WD-TENG with low frictional resistance and high energy conversion efficiency has important application prospects in wind energy harvesting and self-powered sensing systems.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3030011

Authors: Quang Chieu Bui Vincent Consonni Carmen Jiménez Hervé Roussel Xavier Mescot Bassem Salem Gustavo Ardila

Zinc oxide nanowires (ZnO NWs) have gained considerable attention in the field of piezoelectricity in the past two decades. However, the impact of growth-process conditions on their dimensions and polarity, as well as the piezoelectric properties, has not been fully explored, specifically when using pulsed-liquid injection metal–organic chemical vapor deposition (PLI-MOCVD). In this study, we investigate the influence of the O2 gas and DEZn solution flow rates on the formation process of ZnO NWs and their related piezoelectric properties. While the length and diameter of ZnO NWs were varied by adjusting the flow-rate conditions through different growth regimes limited either by the O2 gas or DEZn reactants, their polarity was consistently Zn-polar, as revealed by piezoresponse force microscopy. Moreover, the piezoelectric coefficient of ZnO NWs exhibits a strong correlation with their length and diameter. The highest mean piezoelectric coefficient of 3.7 pm/V was measured on the ZnO NW array with the length above 800 nm and the diameter below 65 nm. These results demonstrate the ability of the PLI-MOCVD system to modify the dimensions of ZnO NWs, as well as their piezoelectric properties.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3030010

Authors: Apostolos Segkos Christos Tsamis

Addressing the increasing development of IoT networks and the associated energy requirements, rotating triboelectric nanogenerators (R-TENGs) are proving to be strong candidates in the field of energy harvesting, as well as to that of self-powered devices and autonomous sensors. In this work, we review the theoretical framework surrounding the operating principles and key design parameters of R-TENGs, while also associating them with their output characteristics. Furthermore, we present an overview of the core designs used by the research community in energy harvesting applications, as well as variations of these designs along with explicit solutions for the engineering and optimization of the electrical output of R-TENGs. Last but not least, a comprehensive survey of the potential applications of R-TENGs outside the energy harvesting scope is provided, showcasing the working principles of the various designs and the benefits they confer for each specific scenario.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3020009

Authors: Muhammad Jahandar Jinhee Heo Soyeon Kim Dong Chan Lim

Indoor organic photovoltaics (IOPVs) have attained considerable research attention as a power source for a low-power consumption self-sustainable electronic device for Internet of Things (IoT) applications. This study aims to develop an efficient cathode interfacial layer (CIL) based on a polyethyleneimine (PEIE) derivative, processed at room temperature, for the advancement of non-fullerene acceptor (NFA)-based IOPVs. Using a simple chemical reaction between polyethyleneimine and cobalt (II) chloride, we developed a 3D network-structured CIL. Through quaternary ammonium salts and chelating, metal ions act as mediators and induce metal-ion doping. An inverted device architecture with wide-bandgap and low-bandgap photo-absorber layer is utilized to understand the role of CILs under standard 1 sun and low-light or indoor light illuminations. The IOPV devices with modified CIL (Co-PEIE) having PBDB-T: IT-M and PBDB-T-2F: BTP-4F photo-absorber layers demonstrate a power conversion efficiency of 22.60% and 18.34% under 1000 lux LED lamp (2700 K) illumination conditions, respectively, whereas the IOPV devices with pristine PEIE CIL realized a poor device performance of 18.31% and 14.32% for the PBDB-T: IT-M and PBDB-T-2F: BTP-4F active layers, respectively. The poor device performance of PEIE interlayer-based IOPV under low-light conditions is the result of the significantly high leakage current and low shunt resistance that directly affect the open-circuit voltage (VOC) and fill factor (FF). Therefore, the adjustable energy barrier and notably low leakage current exhibited by the Co-PEIE CIL have a crucial impact on mitigating losses in VOC and FF when operating under low-light conditions.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3020008

Authors: Wenbin Fu Yice Wang Kanglin Kong Doyoub Kim Fujia Wang Gleb Yushin

Lithium-ion batteries (LIBs) dominate the market of rechargeable power sources. To meet the increasing market demands, technology updates focus on advanced battery materials, especially cathodes, the most important component in LIBs. In this review, we provide an overview of the development of materials and processing technologies for cathodes from both academic and industrial perspectives. We briefly compared the fundamentals of cathode materials based on intercalation and conversion chemistries. We then discussed the processing of cathodes, with specific focuses on the mechanisms of a drying process and the role of the binders. Several key parameters for the development of thick electrodes were critically assessed, which may offer insights into the design of next-generation batteries.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3020007

Authors: Jiayue Zheng Zhi Cao Chengcheng Han Xuelian Wei Linlin Wang Zhiyi Wu

As wearable devices continue to be updated and iterated, there is an increasing demand for energy supplies that are small, portable and capable of working continuously for extended periods of time. Here, a hybrid triboelectric-electromagnetic nanogenerator (HNG) based on a biomechanical energy harvester is demonstrated. The HNG is designed to be worn on the wrist according to the curve of the wearer’s arm swing. During the swinging of the arm, the magnet covered by the PTFE film will move relative to the curved cavity of the HNG and take on a negative charge by rubbing against the inner wall of the Cu coated cavity, resulting in a change in the potential difference between the two copper electrodes on the inner wall of the curved cavity. The movement of the magnet causes the magnetic flux of the three pairs of coils on both sides of the arc track to change to produce the induced electric potential, which converts the mechanical energy generated by the arm swing into electrical energy. After the rational design, the HNG is integrated into a small size device to achieve the collection of biomechanical energy. Several experiments were conducted to verify the HNG’s usability. Experiments show that the HNG takes 90 s to charge from 0 V to 1.2 V for a 1000 μF capacitor. In addition, the HNG can light up 23 LEDs simultaneously and provide a continuous supply of energy to portable electronic devices, such as temperature sensors and electronic watches after the capacitor has stored the energy. Furthermore, the HNG is experimentally verified by volunteers wearing the HNG to achieve continuous and stable output in all three states of slow swing, fast swing and running swing. This work not only provides a useful reference for human biomechanical energy harvesting, but can also provide a continuous, clean source of energy for wearable devices.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3020006

Authors: Xianhao Le Xinge Guo Chengkuo Lee

Facing the energy consumption of a huge number of distributed wireless Internet of Things (IoT) sensor nodes, scavenging energy from the ambient environment to power these devices is considered to be a promising method. Moreover, abundant energy sources of various types are widely distributed in the surrounding environment, which can be converted into electrical energy by micro-nano energy harvesters based on different mechanisms. In this review paper, we briefly introduce the development of different energy harvesters according to the classification of target energy sources, including microscale and nanoscale energy harvesters for vibrational energy sources, microscale energy harvesters for non-vibrational energy sources, and micro-nano energy harvesters for hybrid energy sources. Furthermore, the current advances and future prospects of the applications of micro-nano energy harvesters in event-based IoT systems and self-sustained systems are discussed.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3020005

Authors: Zehuan Wang Shiyuan Liu Zhengbao Yang Shuxiang Dong

Anthropogenetic environmental deterioration and climate change caused by energy production and consumption pose a significant threat to the future of humanity. Renewable, environmentally friendly, and cost-effective energy sources are becoming increasingly important for addressing future energy demands. Mechanical power is the most common type of external energy that can be converted into useful electric power. Because of its strong electromechanical coupling ability, the piezoelectric mechanism is a far more successful technique for converting mechanics energy to electrical energy when compared to electrostatic, electromagnetic, and triboelectric transduction systems. Currently, the scientific community has maintained a strong interest in piezoelectric micro-power generators because of their great potential for powering a sensor unit in the distributed network nodes. A national network usually has a large mass of sensor units distributed in each city, and a self-powered sensor network is eagerly required. This paper presents a comprehensive review of the development of piezoelectric micro-power generators. The fundamentals of piezoelectric energy conversion, including operational modes and working mechanisms, are introduced. Current research progress in piezoelectric materials including zinc oxide, ceramics, single crystals, organics, composite, bio-inspired and foam materials are reviewed. Piezoelectric energy harvesting at the nano- and microscales, and its applications in a variety of fields such as wind, liquid flow, body movement, implantable and sensing devices are discussed. Finally, the future development of multi-field coupled, hybrid piezoelectric micropower generators and their potential applications are discussed.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3010004

Authors: Xiaoyun Zhang Yuxin Liu Xiaoshuang Ma Xiaojin Liu Renyun Zhang Yuqiao Wang

Metal–support interaction (MSI) is considered a key effect of electronic and geometric structures of catalysts on tuning catalytic performance. The oxygen evolution reaction (OER) is a crucial process during energy conversion and storage. However, the OER process requires the help of noble metal catalysts to reduce the reaction overpotential, enhance reactivity with intermediates, and maintain good operating stability. Carbon–supported metal catalysts have been considered candidates for noble metal catalysts for OER. MSI occurs at the interface of carbon supports and metals, affecting the catalytic performance through electronic and geometric modulation. MSI can influence the catalytic performance and change reaction pathways from charge redistribution, electron transfer, chemical coordination and bonding, and steric effect. Connecting MSI effects with the OER mechanism can provide theoretical guidance and a practical approach to the design of efficient catalysts, including the modulation of particle size, morphology, heteroatom doping, defect engineering, and coordination atom and number. Advantage can be taken of MSI modulation between metal compounds and carbon supports to provide guidance for catalyst design.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3010003

Authors: Nguyen Huu Huy Phuc Tran Anh Tu Luu Cam Loc Cao Xuan Viet Pham Thi Thuy Phuong Nguyen Tri Le Van Thang

Zinc–air batteries are promising candidates as stationary power sources because of their high specific energy density, high volumetric energy density, environmental friendliness, and low cost. The oxygen-related reactions at the air electrode are kinetically slow; thus, the air electrode integrated with an oxygen electrocatalyst is the most critical component, and inevitably determines the performance of a Zn–air battery. The aim of this paper was to document progress in researching bifunctional catalysts for Zn–air batteries. The catalysts are divided into several categories: noble metal, metal nanoparticle (single and bimetallic), multicomponent nanoparticle, metal chalcogenide, metal oxide, layered double hydroxide, and non-metal materials. Finally, the battery performance is compared and discussed.

Nanoenergy Advances doi: 10.3390/nanoenergyadv3010002

Authors: Nanoenergy Advances Editorial Office Nanoenergy Advances Editorial Office

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Nanoenergy Advances doi: 10.3390/nanoenergyadv3010001

Authors: Linlin Sun Ziming Wang Chengyu Li Wei Tang Zhonglin Wang

Contact electrification exists everywhere and between every phase of matter. However, its mechanism still remains to be studied. The recent triboelectric nanogenerator serves as a probe and provides some new clues about the mechanism present in solid–solid, solid–liquid, and liquid–liquid contact electrification. The gas–solid model still remains to be exploited. Here, we investigated the contact electrification between gases and solids based on the single-electrode triboelectric nanogenerator. Our work shows that the amount of transferred charges between gas and solid particles increases with surface area, movement distance, and initial charges of particle increase. Furthermore, we find that the initial charges on the particle surface can attract more polar molecules and enhance gas collisions. Since ions in gas–solid contact are rare, we speculate that gas–solid contact electrification is mainly based on electron transfer. Further, we propose a theoretical model of gas–solid contact electrification involving the gas collision model and initial charges of the particle. Our study may have great significance to the gas–solid interface chemistry.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2040018

Authors: Massimo Mariello

Nanogenerators are a recently emerging technology which is able to cost-effectively harvest energy from renewable and clean energy sources at the micro/nano-scale. Their applications in the field of self-powered sensing systems and portable power supplying devices have been increasing in recent years. Wearable and implantable electromechanical/electrochemical transducers for energy harvesting represent a novel alternative to chemical batteries for low-power devices and to exploit the energy conveyed by human biomechanics. The human heart, in particular, is a compelling in vivo source of continuous biomechanical energy and is a natural battery which can power implantable or wearable medical devices. This review describes the recent advances in cardiac wearable/implantable soft and flexible devices and nanogenerators for energy harvesting (piezoelectric nanogenerators, triboelectric nanogenerators, biofuel cells, solar cells, etc.), as well as cardiovascular implantable electronic devices in a more general sense, as components of more complex self-sustainable bioelectronic systems for controlling irregular heartbeats or for interventional therapy for cardiac diseases. The main types of soft heart energy harvesters (HEHs) and heart bioelectronic systems (HBSs) are covered and classified, with a detailed presentation of state-of-the-art devices, and the advances in terms of materials choice, chemical functionalization, and design engineering are highlighted. In vivo bioelectronic cardiac interfaces are outlined as well as soft devices for in vitro cardiac models (patch and organoids). Cutting-edge 3D/4D bioprinting techniques of cardiac tissue are also mentioned. The technical challenges for the practical application and commercialization of soft HBSs are discussed at the end of this paper.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2040017

Authors: Xinlong Huang Youchao Qi Tianzhao Bu Xinrui Li Guoxu Liu Jianhua Zeng Beibei Fan Chi Zhang

In the era of the Internet of Things, various electronics play an important role in information interaction, in which the power supply is an urgent problem to be solved. Triboelectric nanogenerator (TENG) is an emerging mechanical energy harvesting technology that can serve as a power source for electronics, which is developing towards high performance, miniaturization and integration. Herein, the advanced micro-nano manufacturing technologies are systematically reviewed for TENGs. First, film preparation such as physical vapor deposition, chemical vapor deposition, electrochemical deposition, electrospinning and screen printing for triboelectric layers are introduced and discussed. Then, surface processing, such as soft lithography, laser ablation, inductively coupled plasma and nanoimprint for micro-nano structures on the surface of triboelectric layers are also introduced and discussed. In addition, micro-electromechanical system fabrication for TENG devices such as acoustic and vibration sensors, is introduced, and their current challenges are analyzed. Finally, the challenges of the advanced micro-nano manufacturing technologies for the TENGs are systematically summarized, and further development is prospected.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2040016

Authors: Qing Wang Xin Jiang Qijun Tong Haijian Li Jie Li Weiqing Yang

Lithium-ion hybrid capacitors (LICs) possess the fascinating characteristics of both high power density and high energy density simultaneously. However, to design highly compatible cathode materials with a high capacity and anode materials with a high rate performance is still a major challenge because of the mismatch of dynamic mechanisms, greatly limiting the development of LICs. Herein, we report an N−doped porous carbon (N−PC) with a continuously interconnected network as the cathode, matching the dynamic mechanism of the uniquely pseudocapacitive T−Nb2O5 anode without diffusion-controlled behavior. This heteroatom-grafting strategy of the cathode can effectively control the dynamic process to adjust the ion transport efficiency, shortening the gap of kinetics and capacity with the anode. For the energy storage application, the as-prepared N−PC cathode demonstrates an appreciable capacity of 62.06 mAh g−1 under a high voltage window of 3 V to 4.2 V, which can exceed the capacity of 25.57 mAh g−1 for porous carbon without heteroatom doping at the current density of 0.1 A g−1. Furthermore, the as-developed lithium-ion capacitor possesses an outstanding electrochemical performance (80.57 Wh kg−1 at 135 W kg−1 and 36.77 Wh kg−1 at 2.7 kW kg−1). This work can provide a new avenue to design cathode materials with a highly appreciable capacity and highly compatible kinetic mechanism, further developing high-performance lithium-ion capacitors.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2040015

Authors: Sachin Barsiwal Anjaly Babu Uday Kumar Khanapuram Supraja Potu Navneeth Madathil Rakesh Kumar Rajaboina Siju Mishra Haranath Divi Prakash Kodali Raju Nagapuri Thirmal Chinthakuntla

Energy harvesting from the ambient environment can be a beneficial and promising source for powering micro- and nanodevices. Triboelectric nanogenerator (TENG) technology has been proved to be a simple and cost-effective method to harness ambient mechanical energy. The performance of the TENG device mainly depends on the careful selection of the material pair. So far, metals and polymer materials have dominated TENG technology. Recently, there have been few reports on metal–organic framework (MoF)-based TENGs. MoFs are very interesting and offer excellent chemical and thermal stability, besides their unique properties, such as tunable pore size and high surface area. Herein, we report a zeolitic imidazole framework (ZIF-67)-based TENG device for self-powered device applications. We used ZIF-67 as one tribolayer, and PET and PMMA as opposite tribolayers. The output performance of the TENG device fabricated with the PMMA/ZIF-67 pair showed values of 300 V, 47.5 µA, and 593 mW/m2 of open-circuit voltage, short-circuit current, and power density, respectively. To the best of our knowledge, these are the highest reported values so far for ZIF-67-based TENG devices. The fabricated TENG device lit up 250 LEDs and was employed to explore different self-powered device applications.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2040014

Authors: Xiang Zhou Kechao Zhou Dou Zhang Chris Bowen Qingping Wang Junwen Zhong Yan Zhang

Due to the unique electromechanical energy conversion capability of ferroelectric materials, they have been at the forefront of materials science for a variety of applications such as sensors, actuators and energy harvesting. Researchers have focused on exploring approaches to achieve improved ferroelectric performance, and to ensure that the available material systems are more environmentally friendly. This comprehensive review summarizes recent research progress on porous ceramics and highlights the variety of factors that are often ignored, namely the influence of porosity on the Curie temperature, and applications of porous ferroelectric materials with adjustable Curie temperature. Finally, the development trends and challenges of porous ferroelectric materials are discussed, aiming to provide new insights for the design and construction of ferroelectric materials.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2030013

Authors: Xuanyi Dong Zhaoqi Liu Peng Yang Xiangyu Chen

The utilization of various distributed energy is becoming a prominent research topic due to the rapid development of the Internet of Things and wireless condition monitoring systems. Among the various distributed energy sources, wind energy has the advantages of being widely distributed, renewable and pollution-free, and is a very promising mechanical energy for power supply. Traditional wind energy harvesting methods based on electromagnetic and piezoelectric effects have issues with complex structure, large size, severe mechanical structures, and high installation costs. The low frequency and irregular nature of ambient mechanical energy makes these methods generally inefficient and inevitably hinders the further exploitation of wind energy. The triboelectric nanogenerators (TENGs) based on frictional charging and electrostatic effects can also be used for wind power generation and are increasingly favored by researchers as TENGs are easier to be miniaturized and assembled, and can realize large-scale manufacturing in comparison. This paper reviews the research on TENGs for wind energy utilization in terms of structural design, material selection and potential applications. In addition, the potential difficulties and possible developments in this field are summarized and discussed.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2030012

Authors: Ya Yang

Nanoenergies, including mechanical, thermal and solar energies, can be found in our surroundings [...]

Nanoenergy Advances doi: 10.3390/nanoenergyadv2030011

Authors: Yapeng Shi Tianyi Ding Zhihao Yuan Ruonan Li Baocheng Wang Zhiyi Wu

The authors wish to make the following corrections to this paper [...]

Nanoenergy Advances doi: 10.3390/nanoenergyadv2030010

Authors: Daniele Benetti Federico Rosei

Over the last decade, the field of luminescent solar concentrators (LSC) has experienced significant growth, as noted by the increasing number of studies. However, so far, most of the devices developed have only been employed in a simple planar configuration coupled with silicon photovoltaic solar cells. This type of device is essentially a solar window whose main objective is to produce electrical power. However, due to the intrinsic nature of LSC, that is, the ability to absorb, downshift and concentrate the solar radiation that impinges on it, this photonic device can be used in alternative ways. In particular, in this review, we will explore several non-conventional applications in which LSCs are used successfully, including as solar bioreactors for algae development, photo reactors for organic synthesis, and as greenhouses.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2020009

Authors: Seh-Hoon Chung Jihoon Chung Sangmin Lee

A triboelectric nanogenerator (TENG) is a noteworthy mechanical energy harvester that can convert mechanical energy into electricity by combining triboelectrification and electrostatic induction. However, owing to the nature of its working mechanism, TENGs have critical limitations in mechanical and electrical aspects, which prevent them from being utilized as primary power sources. To overcome these limitations, several studies are turning their attention to utilizing lubricants, which is a traditional method recently applied to TENGs. In this review, we introduce recent advances in lubricant-based TENGs that can effectively enhance their electrical output and mechanical lifespan. In addition, this review provides an overview of lubricant-based TENGs. We hope that, through this review, researchers who are trying to overcome mechanical and electrical limitations to expand the applications of TENGs in industries will be introduced to the use of lubricant materials.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2020008

Authors: Andrés Jenaro Lopez Garcia Thomas Jalabert Manojit Pusty Viktor Defoor Xavier Mescot Maria Montanino Giuliano Sico Fausta Loffredo Fulvia Villani Giuseppe Nenna Gustavo Ardila

Zinc oxide (ZnO) nanogenerators have attracted increasing interest in the scientific community for use in energy harvesting and mechanical sensing applications. Understanding the interplay between piezoelectricity and semiconductor physics is fundamental to enhancing these devices’ performances, although direct characterization at the nanoscale is challenging. With this work, we present a new strategy to improve piezoresponse force microscopy (PFM) measurements and analysis. This strategy was applied to study the piezoelectric performances of ZnO nanowires grown on seed layers deposited by gravure printing onto flexible substrates. We demonstrate the influence of nanowire diameter and atomic force microscope (AFM) tip position on the piezoresponse amplitude. We also explain our results with simulations showing the importance of considering semiconducting properties in the analysis.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2020007

Authors: Tingting Jiang Hao Yang George Chen

Silicon is considered as one of the most promising candidates for the next generation negative electrode (negatrode) materials in lithium-ion batteries (LIBs) due to its high theoretical specific capacity, appropriate lithiation potential range, and fairly abundant resources. However, the practical application of silicon negatrodes is hampered by the poor cycling and rate performances resulting mainly from the huge volume change during Li+ insertion/extraction. Various composite structures have been investigated to maintain the structural integrity and improve the stability and electric conductivity of silicon-based negatrodes. Of these, 2D transition-metal carbides, also known as MXenes (e.g., Ti3C2Tx), have become increasingly attractive for energy storage applications because of their excellent electric, electrochemical and mechanical properties and potential uses as the matrix for construction of 3D networks with larger buffering spaces and more effective charge carrier conduction in silicon-based negatrodes. This article reviews specifically composite negatrodes of silicon with titanium-carbide-based MXenes for LIBs from the materials perspective. The structures design, preparation method, interface control, and their effects on electrochemical performances are comprehensively elaborated on. It is shown that the recent development of Si/MXene-based negatrodes presents great potential for future applications.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2010006

Authors: Kai Dong Xiao Peng Renwei Cheng Zhong Lin Wang

By seamlessly integrating the wearing comfortability of textiles with the biomechanical energy harvesting function of a triboelectric nanogenerator (TENG), an emerging and advanced intelligent textile, i.e., smart textile TENG, is developed with remarkable abilities of autonomous power supply and self-powered sensing, which has great development prospects in the next-generation human-oriented wearable electronics. However, due to inadequate interface contact, insufficient electrification of materials, unavoidable air breakdown effect, output capacitance feature, and special textile structure, there are still several bottlenecks in the road towards the practical application of textile TENGs, including low output, high impedance, low integration, poor working durability, and so on. In this review, on the basis of mastering the existing theory of electricity generation mechanism of TENGs, some prospective strategies for improving the mechanical-to-electrical conversion performance of textile TENGs are systematically summarized and comprehensively discussed, including surface/interface physical treatments, atomic-scale chemical modification, structural optimization design, work environmental control, and integrated energy management. The advantages and disadvantages of each approach in output enhancement are further compared at the end of this review. It is hoped that this review can not only provide useful guidance for the research of textile TENGs to select optimization methods but also accelerate their large-scale practical process.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2010005

Authors: Zhirong Liu Zhuo Wang Linlin Li

Bioelectricity is an indispensable part of organisms and plays a vital role in cell modulation and tissue/organ development. The development of convenient and bio-safe electrical stimulation equipment to simulate endogenous bioelectricity for cell function modulation is of great significance for its clinical transformation. In this review, we introduce the advantages of an electromechanical nanogenerator (EMNG) as a source of electrical stimulation in the biomedical field and systematically overview recent advances in EMNGs for cell modulation, mainly including cell adhesion, migration, proliferation and differentiation. Finally, we emphasize the significance of self-powered and biomimetic electrostimulation in cell modulation and discuss its challenges and future prospects in both basic research and clinical translation.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2010004

Authors: Massimo Mariello

Nanogenerators, based on piezoelectric or triboelectric materials, have emerged in the recent years as an attractive cost-effective technology for harvesting energy from renewable and clean energy sources, but also for human sensing and biomedical wearable/implantable applications. Advances in materials engineering have enlightened new opportunities for the creation and use of novel biocompatible soft materials as well as micro/nano-structured or chemically-functionalized interfaces. Hybridization is a key concept that can be used to enhance the performances of the single devices, by coupling more transducing mechanisms in a single-integrated micro-system. It has attracted plenty of research interest due to the promising effects of signal enhancement and simultaneous adaptability to different operating conditions. This review covers and classifies the main types of hybridization of piezo-triboelectric bio-nanogenerators and it also provides an overview of the most recent advances in terms of material synthesis, engineering applications, power-management circuits and technical issues for the development of reliable implantable devices. State-of-the-art applications in the fields of energy harvesting, in vitro/in vivo biomedical sensing, implantable bioelectronics are outlined and presented. The applicative perspectives and challenges are finally discussed, with the aim to suggest improvements in the design and implementation of next-generation hybrid bio-nanogenerators and biosensors.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2010003

Authors: Yapeng Shi Tianyi Ding Zhihao Yuan Ruonan Li Baocheng Wang Zhiyi Wu

Advances in the technology of wearable electronic devices have necessitated much research to meet their requirements, such as stretchability, sustainability, and maintenance-free functioning. In this study, we developed an ultrathin all-fiber triboelectric nanogenerator (TENG)-based electronic skin (TE-skin) with high stretchability, using electrospinning and spraying, whereby the silver nanowire (Ag NW) electrode layer is deposited between two electrospinning thermoplastic polyurethane (TPU) fibrous layers. Due to its extraordinary stretchability and prominent Ag NW conductive networks, the TE-skin exhibits a high sensitivity of 0.1539 kPa−1 in terms of pressure, superior mechanical property with a low-resistance electrode of 257.3 Ω at a strain of 150%, great deformation recovery ability, and exceptional working stability with no obvious fluctuation in electrical output before and after stretching. Based on the outstanding performances of the TE-skin, an intelligent electronic glove was fabricated to detect multifarious hand gestures. Moreover, the TE-skin has the potential to record human motion for real-time physiological signal monitoring, which provides promising applications in the fields of flexible robots, human-machine interaction, and multidimensional sports monitoring in next-generation electronics.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2010002

Authors: Nghia Dinh Huynh Dukhyun Choi

Triboelectric nanogenerators (TENGs) are a promising renewable energy technology. Many applications have been successfully demonstrated, such as self-powered Internet-of-Things sensors and many wearables, and those portable power source devices are useful in daily life due to their light weight, cost effectiveness, and high power conversion. To boost TENG performance, many researchers are working to modulate the surface morphology of the triboelectric layer through surface-engineering, surface modification, material selection, etc. Although triboelectric material can obtain a high charge density, achieving high output performance that is predictable and uniform requires mechanical energy conversion systems (MECSs), and their development remains a huge challenge. Many previous works did not provide an MECS or introduced only a simple mechanical system to support the TENG integration system device. However, these kinds of designs cannot boost the output performance or control the output frequency waveform. Currently, some MECS designs use transmission conversion components such as gear-trains, cam-noses, spiral springs, flywheels, or governors that can provide the step-up, controllable, predictable, and uniform output performance required for TENGs to be suitable for daily applications. In this review, we briefly introduce various MECS designs for regulating the output performance of TENGs. First, we provide an overview of simple machines that can be used when designing MECSs and introduce the basic working principles of TENGs. The following sections review MECSs with gear-based, cam-based, flywheel-based, and multiple-stage designs and show how the MECS structure can be used to regulate the input flow for the energy harvester. Last, we present a perspective and outline for a full system design protocol to correlate MECS designs with future TENG applications.

Nanoenergy Advances doi: 10.3390/nanoenergyadv2010001

Authors: Hugo Gaspar Gabriel Bernardo Adélio Mendes

Over the last four years, tremendous progress has occurred in the field of organic photovoltaics (OPVs) and the champion power conversion efficiency (PCE) under AM1.5G conditions, as certified by the National Renewable Energy Laboratory (NREL), is currently 18.2%. However, these champion state-of-the-art devices were fabricated at lab-scale using highly toxic halogenated solvents which are harmful to human health and to the environment. The transition of OPVs from the lab to large-scale production and commercialization requires the transition from halogenated-solvent-processing to green-solvent-processing without compromising the device’s performance. This review focuses on the most recent research efforts, performed since the year 2018 onwards, in the development of green-solvent-processable OPVs and discusses the three main strategies that are being pursued to achieve the proposed goal, namely, (i) molecular engineering of novel donors and acceptors, (ii) solvent selection, and (iii) nanoparticle ink technology.

Nanoenergy Advances doi: 10.3390/nanoenergyadv1020007

Authors: Jabir Zamir Minhas Md Al Mahadi Hasan Ya Yang

Innovations in nanogenerator technology foster pervading self-power devices for human use, environmental surveillance, energy transfiguration, intelligent energy storage systems, and wireless networks. Energy harvesting from ubiquitous ambient mechanical, thermal, and solar energies by nanogenerators is the hotspot of the modern electronics research era. Ferroelectric materials, which show spontaneous polarization, are reversible when exposed to the external electric field, and are responsive to external stimuli of strain, heat, and light are promising for modeling nanogenerators. This review demonstrates ferroelectric material-based nanogenerators, practicing the discrete and coupled pyroelectric, piezoelectric, triboelectric, and ferroelectric photovoltaic effects. Their working mechanisms and way of optimizing their performances, exercising the conjunction of effects in a standalone device, and multi-effects coupled nanogenerators are greatly versatile and reliable and encourage resolution in the energy crisis. Additionally, the expectancy of productive lines of future ensuing and propitious application domains are listed.