Search Results (14)

This work presents the design, fabrication and characterisation of an improved textile energy storage device implemented in a single layer of polyester cotton and silk fabric. To achieve this, the energy storage device has evolved from an electrical double-layer (EDL) supercapacitor to a zinc-ion supercapacitor (ZHSC) with an optimised co-polymer membrane containing a polyethene oxide (PEO) additive and a polyvinylidene (PVDF)-based organic electrolyte. The flexible textile ZHSC achieved an areal capacitance of 159.5 mF cm⁻² and an energy density of 52.3 µWh cm⁻² (increasing by a factor of 4 and 1.8, respectively, on the previous work) with a power density of 0.27 mW cm⁻² and good bending stability. Full article

Carbon is predominantly used in zinc-ion hybrid capacitors (ZIHCs) as an electrode material. Nitrogen doping and strategic design can enhance its electrochemical properties. Melamine formaldehyde resin, serving as a hard carbon precursor, synthesizes nitrogen-doped porous carbon after annealing. Incorporating transition metal catalysts like Ni, Co, and Fe alters the morphology, pore structure, graphitization degree, and nitrogen doping types/proportions. Electrochemical tests reveal a superior capacitance of 159.5 F g⁻¹ at a scan rate of 1 mV s⁻¹ and rate performance in Fe-catalyzed N-doped porous carbon (Fe-NDPC). Advanced analysis shows Fe-NDPC’s high graphitic nitrogen content and graphitization degree, boosting its electric double-layer capacitance (EDLC) and pseudocapacitance. Its abundant micro- and mesopores increase the surface area fourfold compared to non-catalyzed samples, favoring EDLC and fast electrolyte transport. This study guides catalyst application in carbon materials for supercapacitors, illuminating how catalysts influence nitrogen-doped porous carbon structure and performance. Full article

Aqueous zinc-ion hybrid capacitors (ZIHCs) have emerged as a promising technology, showing superior energy and power densities, as well as enhanced safety, inexpensive and eco-friendly features. Although ZIHCs possess the advantages of both batteries and supercapacitors, their energy density is still unsatisfactory. Therefore, it is extremely crucial to develop reasonably matched electrode materials. Based on this challenge, a surge of studies has been conducted on the modification of carbon-based electrode materials. Herein, we first summarize the progress of the related research and elucidate the energy storage mechanism associated with carbon-based electrodes for ZIHCs. Then, we investigate the influence of the synthesis routes and modification strategies of the electrode materials on electrochemical stability. Finally, we summarize the current research challenges facing ZIHCs and predict potential future research pathways. In addition, we suggest key scientific questions to focus on and potential directions for further exploration. Full article

Zinc-ion capacitors (ZICs), combining the merits of both high-energy zinc-ion batteries and high-power supercapacitors, are known as high-potential electrochemical energy storage (EES) devices. However, the research on ZICs still faces many challenges because of the lack of appropriate cathode materials with robust crystal structures and rich channels for stable and fast Zn²⁺ ion transport. In this study, we synthesized a robust, conductive, two-dimensional metal–organic framework (MOF) material, zinc-benzenehexathiolate (Zn-BHT), and investigated its electrochemical performance for zinc storage. Zn²⁺ ions could insert into/extricate from the host structure with a high diffusion rate, enabling the Zn-BHT cathode to exhibit a surface-controlled charge storage mechanism. Due to its unique structure, Zn-BHT exhibited a good reversible discharge capacity approaching 90.4 mAh g⁻¹ at 0.1 A g⁻¹, as well as a desirable rate capability and good cycling performance. In addition, a ZIC device was fabricated using the Zn-BHT cathode and a polyaniline-derived porous carbon (PC) anode, which depicted a high working voltage of up to 1.8 V and a high energy density of ~37.2 Wh kg⁻¹. This work shows that conductive MOFs are high-potential electrode materials for ZICs and provide new enlightenment for the development of electrode materials for EES devices. Full article

This work reports an encapsulated and flexible solid-state AIC screen printed on top of a polyester–cotton textile. The proposed zinc-ion capacitor (ZIC) arrays were fabricated on top of a polymer-coated polyester–cotton textile with solution-based processes and inexpensive electrodes and electrolyte materials. This battery achieved an energy density of 0.47 μWh·cm⁻² (per device area) or 0.51 mWh·cm⁻² (per active material area) in a galvanostatic cycling test between 0.1 V and 1.8 V. Full article

Zinc-ion hybrid capacitors (ZICs) can achieve high energy and power density, ultralong cycle life, and a wide operating voltage window, and they are widely used in wearable devices, portable electronics devices, and other energy storage fields. The design of advanced ZICs with high specific capacity and energy density remains a challenge. In this work, a novel kind of V, N dual-doped Ti₃C₂ film with a three-dimensional (3D) porous structure (3D V-, N-Ti₃C₂) based on Zn-ion pre-intercalation can be fabricated via a simple synthetic process. The stable 3D structure and heteroatom doping provide abundant ion transport channels and numerous surface active sites. The prepared 3D V-, N-Ti₃C₂ film can deliver unexpectedly high specific capacitance of 855 F g⁻¹ (309 mAh g⁻¹) and demonstrates 95.26% capacitance retention after 5000 charge/discharge cycles. In addition, the energy storage mechanism of 3D V-, N-Ti₃C₂ electrodes is the chemical adsorption of H⁺/Zn²⁺, which is confirmed by ex situ XRD and ex situ XPS. ZIC full cells with a competitive energy density (103 Wh kg⁻¹) consist of a 3D V-, N-Ti₃C₂ cathode and a zinc foil anode. The impressive results provide a feasible strategy for developing high-performance MXene-based energy storage devices in various energy-related fields. Full article

Manganese-based materials have received more attention as cathodes for aqueous zinc ion hybrid capacitors (AZIHCs) due to their advantages such as abundant reserves, low cost, and large theoretical capacity. However, manganese-based materials have the disadvantage of poor electrical conductivity. Herein, a solid-phase method was used to synthesize a hierarchical carbon-coated calcium manganate (CaMn₂O₄/C) network framework as the cathode for AZIHCs. Thanks to the unique structural/componential merits including conductive carbon coating and hierarchical porous architecture, the achieved CaMn₂O₄/C cathode shows an exceptionally long life of close to 5000 cycles at 2.0 A g⁻¹, with a reversible specific capacity of 195.6 mAh g⁻¹. The assembled CaMn₂O₄/C-based AZIHCs also display excellent cycling stability with a capacity retention rate of 84.9% after 8000 cycles at 1.0 A g⁻¹, and an energy density of 21.3 Wh kg⁻¹ at an output power density of 180.0 W kg⁻¹. Full article

With the merits of having excellent safety, being low cost and being environmentally friendly, zinc-ion hybrid supercapacitors (ZHSCs) are expected to be widely used in large-scale energy storage and flexible wearable devices. However, limited by their sluggish kinetic process, ZHSCs suffer from low-specific capacity and poor cycling stability at high cathode mass loading. Herein, a novel designed oxygen-rich hierarchical porous carbon (HPOC) is obtained by a one-step strategy of synchronous activation and templated for high-performance ZHSCs. The fabricated ZHSCs with HPOCs show significant improvement in Zn-ion storage capability, with a capacity of 209.4 mAh g⁻¹ at 0.1 A g⁻¹ and 108.3 mAh g⁻¹ at 10 A g⁻¹. Additionally, the cycling stability is excellent, with 92.3% retention after 4000 cycles. Furthermore, an impressive areal capacity of 1.7 mAh cm⁻² is achieved, even with a high mass loading of 12.5 mg cm⁻². More importantly, the flexible quasi-solid state ZHSCs also show a considerable capability (183.5 mAh g⁻¹ at 0.1 A g⁻¹) and a high energy density of 178.0 Wh kg⁻¹. This promising result suggests a valuable route to produce functional nanocarbon materials for zinc storage applications. Full article

Given the rapid progress and widespread adoption of advanced energy storage devices, there has been a growing interest in aqueous capacitors that offer non-flammable properties and high safety standards. Consequently, extensive research efforts have been dedicated to investigating zinc anodes and low-cost carbonaceous cathode materials. Despite these efforts, the development of high-performance zinc-ion capacitors (ZICs) still faces challenges, such as limited cycling stability and low energy densities. In this study, we present a novel approach to address these challenges. We introduce a three-dimensional (3D) conductive porous carbon framework cathode combined with zinc anode cells, which exhibit exceptional stability and durability in ZICs. Our experimental results reveal remarkable cycling performance, with a capacity retention of approximately 97.3% and a coulombic efficiency of nearly 100% even after 10,000 charge–discharge cycles. These findings represent significant progress in improving the performance of ZICs. Full article

The great interest in developing emerging zinc-ion capacitors (ZIC) for energy storage applications is due to their inexpensiveness and the future necessity for hybrid electrical energy storage devices. The Zn-ion hybrid capacitor device was assembled using boron (B)-doped reduced graphene oxide (B-RGO) material, which acts as the cathode, and pure zinc metal as an anode. This research work aims to study the influence of B-doped reduced graphene oxide (B-RGO) with Aloe vera gel as an electrolyte. The reduced graphene oxide (RGO) and B-RGO electrode active materials were confirmed through X-ray diffraction (XRD), RAMAN, Fourier transformation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and field emission-transmission electron microscopy (FE-TEM) analysis. The surface morphological images reveal that a few-layered nanostructure B-RGO was used in the Zn-ion hybrid capacitor device. The electrochemical performance of the Zn-ion hybrid capacitor was evaluated through cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurements, with a wide active potential range of 0–2 V versus Zn/Zn⁺. The mixture composition of Aloe vera extract and 1M ZnSO₄ electrolyte generated a stable voltage and exhibited good capacitive behavior. The fabricated ZIC coin cell device with the Aloe vera gel semi-gel electrolyte containing ZnSO₄ demonstrated improved Zn⁺ ionic exchange and storage efficiency. Moreover, the B-RGO electrode active material exhibited excellent cycle stability. The simple one-step electrochemical technique is the most suitable process for boron doping into graphene nanosheets for future energy storage applications. Full article

Zinc Aluminate is an excellent dielectric material suitable for a variety of technological applications due to its high-quality factor, low dielectric loss, and appreciable conductivity. Here in this study, the preparation of Zn_1−xM_xAl₂O₄ (M = Cu²⁺, Mg²⁺: x = 0, 0.10) powders were carried out using the citrate-based combustion route. The structural, spectral, optical, stoichiometry composition, and dielectric performance of the synthesized nanoparticles were evaluated to explore the substitution effect of Cu²⁺ and Mg²⁺ ions. It was confirmed from XRD results that all the samples exhibited a monophase spinel structure. The estimated average crystallite size is calculated to be 23 nm. The functional group identification of the samples was monitored by FTIR spectroscopy. Scanning electron microscope (SEM) coupled with energy-dispersive X-ray spectroscopy analysis (EDAX) was utilized to confirm the composition of the samples. UV–Visible absorption spectroscopy demonstrated decrement in the band gap due to doping. Impedance spectroscopy displayed improved dielectric properties for the doped samples. The Cole–Cole plots enlightened the relaxation processes and provided information about the complex electrical behavior of the material. It was established that non-Debye relaxation was found to be prominent in the investigated aluminates. From the electrical parameters obtained, it displays the semiconducting nature of the zinc aluminate particles, and it can be utilized for high-frequency applications such as ceramic capacitors, resonators, and filters in high-frequency electronics. Overall, Zinc Aluminate is a versatile material with potential application in various fields of science and electronics. Full article

Biopolymers are an emerging class of novel materials with diverse applications and properties such as superior sustainability and tunability. Here, applications of biopolymers are described in the context of energy storage devices, namely lithium-based batteries, zinc-based batteries, and capacitors. Current demand for energy storage technologies calls for improved energy density, preserved performance overtime, and more sustainable end-of-life behavior. Lithium-based and zinc-based batteries often face anode corrosion from processes such as dendrite formation. Capacitors typically struggle with achieving functional energy density caused by an inability to efficiently charge and discharge. Both classes of energy storage need to be packaged with sustainable materials due to their potential leakages of toxic metals. In this review paper, recent progress in energy applications is described for biocompatible polymers such as silk, keratin, collagen, chitosan, cellulose, and agarose. Fabrication techniques are described for various components of the battery/capacitors including the electrode, electrolyte, and separators with biopolymers. Of these methods, incorporating the porosity found within various biopolymers is commonly used to maximize ion transport in the electrolyte and prevent dendrite formations in lithium-based, zinc-based batteries, and capacitors. Overall, integrating biopolymers in energy storage solutions poses a promising alternative that can theoretically match traditional energy sources while eliminating harmful consequences to the environment. Full article

A single production of nitrogen-doped graphene nanosheets was developed in this present work from a spent Zn-C primary battery. The electrochemically exfoliated nitrogen-doped graphene nanosheets (EC-N-GNS) was applied in supercapacitor symmetric devices. As-prepared EC-N-GNS was utilized for a symmetric supercapacitor with natural seawater multivalent ion electrolyte. The recycling of graphite into nitrogen-doped graphene was characterized by X-ray diffraction and RAMAN spectroscopy. The few-layered morphological structures of EC-N-GNS were analyzed by field emission scanning electron microscope and field emission transmission electron microscope. The electrochemical analysis of the cyclic voltammetry curves observed an electrochemical double-layer capacitor (EDLC) behavior with a potential window of −0.8 V to +0.5 V. The electrochemical galvanostatic charge—discharge study was obtained to be maximum specific capacitance (Csp)—67.69 F/g and 43.07 F/g at a current density of 1 A/g. We promising the facile single-step electrochemically exfoliated EC-N-GNS was obtained from a waste zinc-carbon primary battery to recycle the graphite electrodes. The superior electrochemical performance comparatively bulk graphite and EC-N-GNS for potential energy storage supercapacitor applications. Full article

The hybrid ion capacitor (HIC) is a hybrid electrochemical energy storage device that combines the intercalation mechanism of a lithium-ion battery anode with the double-layer mechanism of the cathode. Thus, an HIC combines the high energy density of batteries and the high power density of supercapacitors, thus bridging the gap between batteries and supercapacitors. Two-dimensional (2D) carbon materials (graphite, graphene, carbon nanosheets) are promising candidates for hybrid capacitors owing to their unique physical and chemical properties, including their enormous specific surface areas, abundance of active sites (surface and functional groups), and large interlayer spacing. So far, there has been no review focusing on the 2D carbon-based materials for the emerging post-lithium hybrid capacitors. This concept review considers the role of 2D carbon in hybrid capacitors and the recent progress in the application of 2D carbon materials for post-Li (Na⁺, K⁺, Zn²⁺) hybrid capacitors. Moreover, their challenges and trends in their future development are discussed. Full article