Search Results (775)

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. Full article

Aluminum–silicon (Al-Si) alloys are widely used in aerospace, automotive manufacturing, power electronics, marine engineering and other fields due to their excellent physical properties. However, their corrosion resistance is insufficient in harsh service environments. In this study, a variety of characterization methods were adopted, including scanning electron microscopy (SEM), X-ray diffraction (XRD), electrochemical measurements (electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization), immersion corrosion tests, and scanning vibrating electrode technique (SVET). The results show that the appropriate heat treatment regime can significantly enhance the corrosion resistance of the alloy, while improper aging parameters will aggravate the corrosion tendency. The optimal heat treatment regime is solution treatment at 500 °C for 4 h followed by aging at 200 °C for 48 h. Under this condition, the corrosion current density (i_corr) is as low as 79.30 μA/cm², and the low-frequency impedance modulus and phase angle in EIS tests are optimal. The as-extruded alloy exhibits severe localized corrosion, while the heat-treated alloy transforms into mild and uniform corrosion. The underlying mechanism is that heat treatment induces the formation of uniformly distributed nanoscale Mg₂Si and Al₃(Sc,Zr) precipitates, which synergistically improve the corrosion resistance of the alloy by weakening micro-galvanic coupling and facilitating the formation of a stable passive film. Full article

With the advancement of automation and intelligent manufacturing, mechanical vibration monitoring has become crucial for equipment health assessment. This study proposes a triboelectric nanogenerator (TENG)-based vibration sensor featuring a silicone rubber composite structure. The sensor comprises a silicone rubber layer sandwiched between polyethylene terephthalate (PET) films backed by conductive fabric electrodes, all supported on a polylactic acid (PLA) arch frame. Through systematic structural optimization, the device employing Dragon Skin-30 silicone (1 mm thickness) and conductive fabric electrodes achieved a significant enhancement in output voltage and superior sensitivity compared to initial designs. The optimized sensor operates over a broad detection range for acceleration (5–50 m/s²), amplitude (0.1–2 mm), and frequency (1–300 Hz), and exhibits high linearity (R² ≥ 0.97974) in acceleration sensing. Quantitative comparison with existing triboelectric nanogenerator (TENG) vibration sensors confirms that the proposed SR-TENG outperforms most reported devices in terms of comprehensive detection range and linear sensing performance. Durability tests over 2 h confirmed stable output without degradation. Practical validation on marine blower equipment demonstrated accurate frequency monitoring, closely matching actual vibration characteristics. This work presents a novel approach to self-powered vibration sensing and supports the development of intelligent, sustainable industrial monitoring systems. Full article

This study reports a graphite-core, multiphase gradient C–Si–N composite architecture for Si-containing graphite-based negative electrodes in lithium-ion batteries. The increase in electrode thickness is used as a practical metric of expansion-driven degradation. The composite is prepared by the simultaneous nitridation and carbonization of a graphite core–Si precursor using polyvinylpyrrolidone (PVP) as the N source. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy indicates a quasi-continuous radial trend in the relative N signal toward the outer shell, consistent with preferential N enrichment near the particle exterior. This spatially distributed N arrangement may spatially separate the Si-rich expansion-prone region from the carbon-rich exterior containing nitrides and other N-bearing species, thereby enabling stress partitioning. The shell architecture is designed to disperse expansion-induced stress and stabilize the electrode–electrolyte interface. During electrochemical cycling, the C–Si–N electrode with 10% PVP preserves its core–shell morphology and exhibits the smallest average electrode thickness expansion (~58% after 40 cycles, based on four independent cells). The reduced thickness growth is discussed in relation to a mechanically robust Si–N matrix (Si₃N₄-like/SiN_x-like), potential Li–N interphase species, and N-containing carbon, together with the post-mortem morphology and electrochemical impedance evolution. This study presents reduced swelling as an electrode-level trend versus nominal PVP addition, along with associated nitride-related signatures, thereby highlighting spatially graded stress buffering as an electrode-level design principle. Full article

Neural interfaces created using thin-film fabrication rely primarily on conductive metal traces for electrical interconnects. Here, we explore the use of tantalum (Ta) metal interconnects as a replacement for noble-metal interconnects such as Au, Pt or Ir. Ta has been investigated previously for interconnect metallization in flexible silicon ribbon cables, but the structure and properties of tantalum for neural device metallization have not been extensively reported. In the present work, Ta metal was sputter-deposited onto amorphous silicon carbide (a-SiC), with and without a base titanium (Ti) adhesion layer, and investigated as interconnect metallization. In the absence of a Ti adhesion layer, resistivity measurements revealed a factor of six difference between Ta resistivity depending on the presence of the Ti base layer, with direct deposition on a-SiC nucleating high resistivity β-Ta (ρ = 197 ± 31 µΩ·cm, mean ± standard deviation) and Ta deposited on Ti nucleating low resistivity α-Ta (ρ = 35 ± 6 µΩ·cm). X-ray diffraction confirmed the existence of the two crystal structures. Ta feature sizes of 2 µm were created using photolithography and reactive ion etching (RIE). Finally, planar microelectrode array test structures using α-Ta and Au trace metallization with low-impedance ruthenium oxide (RuO_x) electrodes were fabricated and investigated by cyclic voltammetry (CV) and current pulsing in saline. These devices underwent 500 CV cycles between −0.6 and +0.6 V without evidence of degradation. In response to charge-balanced, biphasic current pulses at 4 nC/phase, a 21 mV increase in access voltage was observed with α-Ta metallization compared to Au. These results warrant further investigation of Ta as thin-film metallization interconnects for neural interface devices. Full article

Trace amounts of H₂O are inevitably introduced during lithium battery manufacturing processes, which induces the hydrolysis of LiPF₆, leading to HF formation, which triggers a cascade of deleterious reactions that degrade the solid electrolyte interphase (SEI) and corrode electrode materials. In this work, a water-scavenging electrolyte was constructed by employing a boroxine-linked covalent organic framework (COF) as the suspended phase. The ring-opening reaction of the boroxine ring units in COFs can effectively capture H₂O, thereby suppressing the hydrolysis of PF₆⁻ and mitigating electrode corrosion caused by HF. Consequently, a Li-metal battery with a high-nickel cathode retained 73% of its initial capacity after 500 cycles at 1 C, and a silicon-based lithium-ion battery with a high-nickel cathode sustained stable cycling over 500 cycles at a high rate of 10 C. This suspension strategy, leveraging a boroxine-linked COF with dual H₂O-scavenging capability, offers a scalable and versatile platform for electrolyte engineering toward practical next-generation lithium batteries. Full article

Silicon-based materials offer exceptional theoretical capacity for lithium-ion batteries (LIBs), but their practical application remains severely hindered by large volume expansion, low electrical conductivity, and unstable solid electrolyte interphase (SEI) formation during cycling. Herein, a binder-free silicon-containing carbon composite anode (denoted as CP-Si@C-4, where CP represents the conductive carbon paper substrate) is designed: carbon constitutes the structural and conductive framework, while silicon nanoparticles serve as a functional alloying component contributing characteristic lithiation/delithiation behavior. This framework comprises a conductive carbon paper (CP) scaffold, a resin-derived carbon matrix for homogeneous silicon dispersion, an interconnected carbon nanotube (CNT) network enabling long-range electron transport, and a conformal chemical vapor deposition (CVD) carbon layer for interfacial stabilization. Rather than simply increasing the overall carbon content, a series of control electrodes with distinct carbon configurations are deliberately designed to decouple the respective roles of bulk stress buffering and particle-level interfacial stabilization during cycling. The results indicate that functionally differentiating and coordinately regulating these two functions is critical for achieving durable binder-free silicon-containing carbon composite anodes. Benefiting from this cooperative multidimensional carbon architecture, the optimized CP-Si@C-4 anode delivers an initial Coulombic efficiency (ICE) of 86.3% and maintains a reversible capacity of ~990 mA h g⁻¹ at 2 A g⁻¹ after 1000 cycles. This work provides a structural design concept for improving long-term stability in binder-free silicon-containing carbon composite anodes. Full article

The photovoltaic industry generates a substantial amount of high-purity waste silicon powder during the diamond-wire saw cutting process, which can serve as an environmentally friendly and cost-effective resource for lithium-ion battery recycling. However, its commercial application is hindered by the surface attachment of silicon dioxide, organic substances, metal impurities, as well as its intrinsic drawbacks such as significant volume expansion (>300%) during lithium (de)intercalation and low electronic conductivity. To address these issues, this study first purifies the waste silicon powder and then designs the structure of the composites. Using a simple ball-milling combined with sol-gel method, a core-shell composite material with a carbon-coated two-dimensional conductive network (FVW-Si/G₅₀₀@C) was synthesized. The two-dimensional conductive network provides sufficient space to accommodate the volume expansion of silicon, while the mesoporous structure on the carbon shell offers a fast transport pathway for Li⁺, thereby enhancing the electrode kinetics. The prepared FVW-Si/G₅₀₀@C electrode maintained a high reversible capacity of 951.8 mAh g⁻¹ after 100 cycles at a current density of 0.2 A g⁻¹. Even at a high current density of 1 A g⁻¹, it retained a reversible capacity of 230.4 mAh g⁻¹. The results indicated that the synergistic effect between graphite sheets and the mesoporous carbon shell significantly improved the rate performance and cycling stability of the FVW-Si/G₅₀₀@C electrode. This study provided a theoretical foundation for the scalable, green, and high-value utilization of waste silicon powder in the photovoltaic industry and offered technical support for sustainable energy development. Full article

Silicon (Si) has attracted extensive attention as a promising anode material for next-generation lithium-ion batteries (LIBs) due to its ultra-high theoretical capacity, low lithiation potential, and economic advantages. However, drastic volume expansion during cycling and slow reaction kinetics severely compromise its structural stability and practical application. Recently, two-dimensional (2D) MXenes have been explored as effective functional components in Si-based electrodes because of their excellent electrical conductivity, high specific surface area, adjustable surface terminations, and mechanical robustness. When integrated with Si, MXenes serve as conductive matrices that alleviate volumetric stress, enhance charge transport, and accelerate electron/ion diffusion. Consequently, Si/MXene nanocomposites (NCs) exhibit significantly improved lithium (Li) storage performance. This review outlines recent advances in Si/MXene NCs, covering fabrication strategies, structural engineering, and various configurations, including particulate materials, three-dimensional (3D) architectures, films, and fibrous systems, and establishes the relationship between structural design and electrochemical behavior. Remaining challenges and prospective research directions are also discussed to guide the development of high-energy-density LIB anodes. Full article

Peripheral nerve regeneration is most rapid during the early post-injury period but gradually slows over time, often limiting functional recovery. Electrical stimulation (ES) delivered via percutaneous needle electrodes has been shown to modulate the local neural microenvironment and promote axonal regeneration; however, the optimal temporal window and duration of stimulation remain unclear. This study aimed to evaluate the time-dependent effects of needle-based ES on peripheral nerve regeneration in a rat model of sciatic nerve transection, using a well-established silicone nerve conduit as a stable and reproducible non-biodegradable repair model. Female Sprague–Dawley rats underwent sciatic nerve transection and repair. Postoperatively (PO), animals were randomly assigned to control (C) needle insertion or needle-based ES groups, receiving stimulation for either 3 weeks (C-3W-PO and ES-3W-PO, respectively) or 7 weeks (C-7W-PO and ES-7W-PO, respectively). Functional recovery was evaluated using cold plate latency and rotarod performance tests. Electrophysiological assessments included measurements of nerve conduction velocity (NCV), compound muscle action potential amplitude, and muscle action potential (MAP) area. Histomorphometric analysis of regenerated nerve tissue quantified total nerve cross-sectional area, endoneurial space, axon number, and axon density. Retrograde labeling with fluoro-gold (FG) was used to quantify reinnervated motor neurons. Immunohistochemical analyses of calcitonin gene-related peptide (CGRP) and macrophage-associated markers were conducted to assess sensory neuropeptide expression and immune cell infiltration within the regenerated nerve. ES significantly improved both sensory and motor recovery in a duration-dependent manner. Behavioral data showed increased cold pain thresholds and improved motor coordination in ES groups, with the most pronounced functional gains observed in the ES-7W-PO group. Electrophysiological measures revealed higher NCV, amplitude, and MAP area in ES-treated animals, with the most pronounced improvements at 7 weeks. Morphologically, ES enhanced nerve regeneration, as evidenced by increased total and endoneurial areas, axonal counts, and axon density. FG-labeled neuron counts were significantly elevated in ES groups, indicating enhanced motor reinnervation. At 3 weeks, ES induced higher CGRP expression and macrophage density, suggesting transient activation of sensory-associated and pro-regenerative immune responses during the early post-injury phase. These findings demonstrate that ES accelerates peripheral nerve repair in rats and that sustained stimulation across the early regenerative window yields superior structural and functional outcomes. Full article

As the demand for clean water grows, the strategic management of water resources has become increasingly critical. However, the depletion of these resources is being accelerated by anthropogenic pollutants and resultant internal pipe corrosion within distribution networks. Conventional water treatment methods are characterized by high energy consumption, rendering them impractical in environments lacking a continuous external power supply. Consequently, innovative, self-sustained technologies for simultaneously monitoring fluid conditions and purifying water are a necessity. In this work, we present a water-driven triboelectric nanogenerator (W-TENG) used for energy harvesting and water-quality monitoring within pipe networks. Composed of a silicone rubber tube and aluminum electrodes, the optimized W-TENG achieved an open-circuit voltage of 58 V, short-circuit current of 1.1 µA, and 59.5 mW/m² at a 10 MΩ load. The W-TENG distinguishes pH levels and liquid types based on electrical outputs. Notably, a parallel connection of two W-TENGs enhanced electrical energy by 214% compared to the sum of two units. As an application, a self-powered electrochemical deposition was conducted and copper ions were successfully removed using energy stored in a 1 mF capacitor. These results indicate that the W-TENG is expected to be utilized as a self-powered platform for simultaneous water purification and real-time infrastructure monitoring. Full article

In this study, we investigated the electrochemical properties and performance characteristics of Co_xS_y and silicon–carbon-based heterostructures synthesized on nickel foam substrates for energy storage applications. Cobalt sulfide films were successfully electrodeposited on nickel foam (NF) using cyclic voltammetry (CV) from the solutions with different Co²⁺ concentrations. The presence of a silicon–carbon sublayer promotes the deposition of cobalt sulfide material. The amorphous phase of α-CoS was observed by the X-ray diffraction technique. Raman spectroscopy confirmed the formation of CoS and CoS₂ phases. A significant increase in electrode areal capacitance is observed with the silicon–carbon film sublayer from 0.5 to 1.3 F·cm⁻² and from 1.6 to 2.3 F·cm⁻² at 3 mA·cm⁻² for samples prepared from solutions with CoCl₂·6H₂O concentrations of 0.005 M and 0.02 M, respectively. In the case of gravimetric capacitance, an increase is observed in the presence of a silicon–carbon sublayer for the SiC@CoS_0.005 sample, rising from 690 F·g⁻¹ to 748 F·g⁻¹ at 4 A·g⁻¹. Conversely, the SiC@CoS_0.02 sample shows a decrease from 1287 F·g⁻¹ to 6590 F·g⁻¹. It was shown that the capacitance of all the electrodes derives from the mix of diffusion-controlled and surface-controlled capacitance processes. The electrochemical impedance spectroscopy (EIS) analysis indicates that the formation of heterostructure materials significantly alters the electrochemical properties by reducing both R_f and R_s. Full article

This work presents the development of an automated and portable monitoring system for the point-of-need detection of tebuconazole and lambda-cyhalothrin. The system features nanoparticle/aptamer-modified electrochemical sensors that are integrated into a microfluidic chip based on polydimethylsiloxane (PDMS). More specifically, rapid and selective detection of both pesticides is achieved using target-specific aptamers immobilized on two-dimensional platinum nanoparticle films that serve as expanded nano-gapped electrodes to enhance sensor sensitivity. The effect of the device substrate (i.e., silicon versus flexible substrates) and measurement setup on biosensing performance has also been investigated. The final monitoring system is characterized by high sensitivity and selectivity in the cases of both target analytes and substrates. Τhe system features a limit of detection of 9.85 pM for tebuconazole, which is one of the lowest reported values in the literature; for lambda-cyhalothrin, it is worth noting that the results reported herein represent one of the few studies on an electrochemical aptamer-based sensor for this analyte, featuring a limit of detection of 48.5 pM. The system is also capable of selectively detecting both targets for complex cross-reactive sample matrices consisting of commercially available pesticides. Moreover, its use could be expanded to detect additional pollutants by functionalizing the biosensor surface with appropriate aptamers. Full article

High-quality spectral filters with versatile tuning mechanisms are essential for applications in photonic integrated circuits, including sensing, laser stabilization, and spectral signal processing. We report the implementation of thermo-optic (TO) and electro-optic (EO) spectral tuning in silicon nitride Mach–Zehnder interferometers (MZIs) and micro-ring resonators (MRRs) by functionalizing the devices with a PMMA:JRD1 polymer cladding and integrating titanium tracks as heaters and electrodes. The fabricated MZIs and MRRs exhibit narrow linewidths of 25–30 pm and achieved TO tuning efficiencies of 1.7 and 13 pm/mW and EO tuning efficiencies of 0.33 and 1.6 pm/V, respectively. Closed-loop regulation using TO and EO effects enables stable half-fringe locking under environmental perturbations. This simple, broadly compatible hybrid platform demonstrates a practical approach to dual-mode spectral tuning and modulation in integrated photonic filters, providing a flexible route toward compact, reconfigurable, and environmentally robust photonic circuits. Full article

Silicon is a well-known anode material for lithium-ion batteries that has attracted a lot of interests because of its high theoretical specific capacity (4200 mAh g⁻¹). However, its severe volume expansion during cycling leads to structural degradation and rapid capacity fading. The design of porous silicon architectures has emerged as a fundamental and effective strategy to mitigate these issues by accommodating mechanical stress and preserving electrode integrity. Concurrently, the development of advanced in situ/operando characterization techniques has shifted the research paradigm, enabling direct observation of dynamic structural and interfacial evolution under operating conditions. This review systematically summarizes recent progress in the rational design of porous Si-based anodes and critically examines how state-of-the-art in situ methods provide direct mechanistic validation of these designs. The work highlights the synergistic interplay between targeted material engineering and in situ/operando characterization, offering a roadmap for the development of high-performance porous silicon anodes. Full article