With the increasing demand for flexible electronic devices, smaller and lighter flexible supercapacitors have gained significant research attention. Among the various materials, self-supporting reduced graphene oxide (rGO) paper has emerged as one of the most promising electrode materials for supercapacitors due to its low cost, high chemical/thermal stability, and excellent electrical conductivity. Nevertheless, a major drawback of rGO paper is the limited ion diffusion between stacked rGO layers, hindering the effective formation of electrochemical double-layer at the electrode/electrolyte interface. In this study, we prepared the rGO paper derived from ball-milled followed-by water oxidation process for reducing the sheet size. The smaller-sized rGO sheets facilitated ion transport between graphene layers, promoting efficient electric double-layer formation. Moreover, the increased presence of edge planes in ball-milled rGO sheets achieved high capacitance, further enhancing the performance of rGO as an electrode material. Notably, the 2-BMOX rGO paper obtained from ball-milling and wet-oxidized graphite exhibited a capacitance of 117.9 F/g in cyclic voltammetry (CV) and 128.6 F/g in galvanostatic charge–discharge (GCD) tests, approximately twice that of conventional rGO. Additionally, the capacitance retained 91% of its initial performance after 2,000 cycles, indicating excellent cycling stability.

Improving the oxygen evolution reaction (OER) performance or replacing OER with the value-added conversion of biomass is of great significance for the green hydrogen energy production. In this work, bimetallic species-decorated laser-induced graphene (LIG) was fabricated and demonstrated as the self-supported electrodes towards efficient OER and 5-hydroxymethylfurfural oxidation reaction (HMFOR). Three-dimensional LIG was obtained via one-step irradiation process under ambient conditions, and active metal species were then introduced through electrodeposition, with Ni-based catalyst as the primary catalytic material and Fe and Co as modified metals. Among, LIG-NiFe electrode achieved an extremely low overpotential of 241.7 mV at a current density of 20 mA/cm2 for OER and demonstrated long-term stability. This could be attributed to the promoted formation of Ni3+ active centers by Fe modified and the intrinsic porous structure of LIG providing an enhanced surface area. As for LIG-NiCo, due to the low onset potential of Co for HMF, it could achieve 99.6% HMF conversion and yielded value-added 2, 5-furandicarboxylic acid (FDCA) with a selectivity of 87.1%. Coupled with the merit of facile fabrication of LIG framework, this study demonstrates that LIG-based electrodes assume great practical application value in electrocatalytic reactions.

A flexible heater with high thermal efficiency and mechanical durability was developed by fabricating laser-induced porous graphene (LIPG) electrodes on polyimide films using a 532 nm green laser. Laser power, scan speed, and line distance were precisely optimized based on photothermal simulations to generate uniform porous graphene structures with large surface area and excellent heat dissipation characteristics. Raman, X-ray diffraction, and X-ray photoelectron spectroscopy analyses confirmed that the optimized LIPG exhibited highly graphitized features with low oxygen defects. Scanning electron microscope analysis revealed that porous morphologies formed only within a specific laser scan speed range, whereas excessive or insufficient irradiation resulted in collapsed or absent porosity. The serpentine-patterned LIPG heater maintained stable electrical resistance under repeated multidirectional bending, demonstrating excellent flexibility and mechanical stability. The heater also achieved rapid and uniform heating up to 80 °C within seconds, maintaining consistent temperature distribution even on curved surfaces.

Enhancing the energy density of electrodes by increasing thickness and mass loading is a technological challenge. Thick electrodes suffer from severe deterioration in electrochemical performance due to insufficient structural integrity and sluggish charge transport, particularly under high current density. Herein, we fabricated thick LiFePO4 (LFP) electrodes with thicknesses ranging from 85.7 to 90.3 μm and an average mass loading of 17.68 mg/cm2 by tailoring the ratio of zero-dimensional (Super P, SP) and one-dimensional (multi-walled carbon nanotube, MWCNT) conductive additives. The electrodes containing MWCNT exhibited crack-free structure and enhanced electrochemical performance with increasing MWCNT ratio because of the superior mechanical properties and electrical conductivity of MWCNT. However, the electrochemical performance of the electrode containing only MWCNT deteriorated due to aggregation of the MWCNT and poor point to point contact with the LFP particles. The multi-dimensional conductive additives improve the dispersion of components within the electrode and the structural stability of the electrode. As a result, the tailored electrode exhibited a lower degree of electrode thickness expansion (1.4 %), lower polarization (60.8 mV at 0.1 C), excellent high-rate capability (132.7 mAh/g at 2 C), superior capacity retention (27.5 % at 3 C), and lower electrical resistivity and interfacial resistance (14.9 Ω cm and 3.8 Ω cm2, respectively) compared to other samples.

Carbon electrodes, renowned for their excellent moisture and air stability, present a compelling alternative to unstable hole transport materials and costly metal electrodes. In carbon electrode-based perovskite solar cells (C-PSCs), organic materials play a crucial role in optimizing the surface characteristics and electrochemical performance of carbon electrodes, thereby enhancing the photoelectric conversion efficiency. By incorporating organic material additives to modulate the pore structure and surface chemistry of carbon electrodes, the processes of photon absorption and electron transport can be effectively promoted, leading to an improvement in device performance. This article comprehensively reviews the latest research progress of organic C-PSCs, covering their device structures, working principles, as well as the modification methods, advantages, and application effects of organic materials in different layers of C-PSCs. Finally, the applications of in-situ characterization and first-principles calculations in this field are briefly introduced, providing theoretical and experimental support for in-depth research. Based on the above research and analysis, optimization strategies such as enhancing charge selectivity, improving the contact between the electrode and the perovskite layer, and enhancing the quality of the perovskite layer are proposed to drive the further development of organic C-PSCs.

Enhancing the energy storage capabilities of supercapacitors (SCs) while preserving their electrochemical performance is crucial for their widespread application. Our research focuses on developing Sb-modified tin oxide (ATO) nanoparticles via a scalable hydrothermal process, offering substantial potential in this domain. The tetragonal nanoparticle structure provides abundant active sites and a highly porous pathway, facilitating rapid and efficient energy storage. Additionally, tin's varied oxidation states significantly enhance redox capacitance. Electrochemical measurements demonstrate ATO's promise as an advanced SC electrode, achieving a peak specific capacitance of 332 F/g at 3 mA/cm2, with robust redox capacitance confirmed through kinetic analysis. Moreover, the ATO electrode exhibits exceptional capacitance retention over 2000 cycles. This study establishes ATO as a leading candidate for future energy storage applications, underscoring its pivotal role in advancing energy storage technologies.

Transition metal/porous carbon composite is good electrode candidate since porous carbon provides high surface porosity which promotes the access of electrolyte ions, and transition metal enables redox reactions to improve specific capacitance and energy density. In this study, iron/carbon nanofiber (CNF) composite electrodes were prepared by grafting ferrocenecarboxaldehyde to the CNFs which were fabricated by electrospinning and thermal treatment of polyacrylonitrile (PAN). The presence of iron on the CNF surface was confirmed by SEM/EDS, ICP-MS and XPS. Electrochemical performance was evaluated using a three-electrode cell with 1 M Na2SO4 as an electrolyte. Iron-grafted CNFs exhibited a high specific capacitance of 358 F g− 1 and an energy density of 49.7 Wh kg− 1 at 0.5 A g− 1, which is significantly higher than those for untreated CNFs (68 F g− 1 and 9.4 Wh kg− 1). This demonstrates that this iron/CNF composite is promising candidate for supercapacitor electrode with outstanding energy storage performance.

Oxyfluorination treatment was used to enhance the electrochemical properties of SiOx/C-based lithium-ion battery anode materials by improving the dispersibility of multi-walled carbon nanotubes, which are conductive materials. The dispersibility, chemical, and morphological characteristics of the oxyfluorinated carbon nanotubes were confirmed through various analyses. In addition, the effect of oxyfluorination was analyzed by a lithium-ion battery performance test, and the discharge capacity and cycling stability were significantly improved. The introduction of oxygen functional groups onto the surface of the carbon nanotubes improved their dispersibility. The fluorine functional groups also acted as catalysts for the introduction of these oxygen functional groups onto the surface and improved the cycling stability by forming a LiF-based solid electrolyte interphase layer. The high discharge capacity and improved cycling stability of these lithium-ion batteries were attributed to the enhanced dispersibility of carbon nanotubes induced by oxyfluorination and the resulting enhancement of the 3D network in the anode material promoting the movement of lithium ions and electrons.

Graphene aerogels have gained widespread recognition in recent years as electrode materials for supercapacitors, primarily attributed to their excellent stability and impressive specific capacitance. However, further enhancing their specific capacitance is a formidable task. One viable strategy to overcome this hurdle is to composite them with metal oxides. In doing so, the metal oxides boost the specific capacitance of graphene aerogels, while the latter addresses the stability issues inherent in metal oxides. This article reviews recent research on Ni, Co, and Mn oxide–graphene composite aerogels in supercapacitors, summarizing their preparation processes, performance and energy storage mechanism. While existing studies have demonstrated the feasibility of metal oxide–graphene composite aerogels as supercapacitor electrodes, several challenges remain, necessitating deeper exploration by researchers in this field.

Supercapacitors, renowned for their high power density and rapid charge-discharge rates, are limited by their low energy density. This limitation has prompted the need for advanced electrode materials. The present study investigated reduced graphene oxide (rGO) in two distinct structures, as a film and as an aerogel, for use as supercapacitor electrodes. The rGO film, prepared by vacuum filtration and thermal reduction, exhibited a compact, lamellar structure, while the aerogel, synthesized through hydrothermal treatment, was a highly porous three-dimensional network. Electrochemical analyses demonstrated the aerogel’s superior performance, as shown by a specific capacitance of 121.2 F/g at 5 mV/s, with 94% capacitance retention after 10,000 cycles. These findings emphasize the importance of structural design in optimizing ion accessibility and charge transfer. They also demonstrate the potential of rGO aerogels for increasing the energy storage efficiency of advanced supercapacitor systems.

Wearable electronics have been the focus of considerable interest in various fields, such as human-machine interfaces, soft robotics, and medical treatments, due to their flexibility, stretchability, and light weight. To address the shortcomings of existing metal thin film-based wearable devices, stretchable conductive polymers have been developed. In particular, double networking hydrogels are being actively studied as a polymer with a three-dimensional stereoscopic structure that can be patterned. Nonetheless, they have shortcomings such as poor electrical properties and cumbersome manufacturing processes, making it difficult to apply them in electronic devices. Herein, we report 3D-printed stretchable electrodes enabled by a titanium/polyacrylamide-alginate-based hydrogel nanocomposite. This research suggests the strategy for resolving the challenges of high costs and complex fabrication processes associated with stretchable electrode, providing a solution to accelerate the commercialization of wearable electronic devices.

We report the synthesis of bimetallic Cu-Au nanotubes (NTs) and Cu@Au core-shell nanowires (NWs) for use as anti-oxidative electrodes. The fabrication involved two key approaches: galvanic replacement to produce Cu-Au NTs and the physical deposition of Au to form Cu@Au core-shell NWs. The galvanic replacement process generated hollow NTs through the Kirkendall effect, driven by the unequal diffusion rates of Cu and Au during the redox reaction. In contrast, the physical deposition of Au, facilitated by fast reduction kinetics using L-ascorbic acid, enabled the formation of a Au shell encapsulating the Cu NWs, preserving their structural integrity. Morphological and structural analyses confirmed the successful formation of both nanostructures. While the Cu-Au NTs exhibited hollow interiors and increased dimensions, the Cu@Au NWs displayed a solid core-shell morphology with minimal diameter increase. Electrical conductivity and thermal stability tests revealed the superior performance of the Cu@Au NWs. The sheet resistance of Cu@Au NWs remained as low as 4 Ω sq-1 and showed exceptional thermal stability, with minimal resistance variation (R/Ro ~1.36) even after 36 h at 120 °C under ambient conditions. In contrast, the Cu-Au NTs suffered rapid oxidation and structural instability. The physical deposition approach holds significant promise for the development of robust, low-resistance electrodes for long-term applications in harsh environments.

Graphene-based solar cells and supercapacitors integrated into photosupercapacitors represent a pioneering advancement. These devices leverage the exceptional properties of graphene, such as high conductivity and large surface area, to enhance both solar energy conversion and energy storage. The integration of these technologies into photosupercapacitors creates a multifunctional device capable of harnessing solar energy and storing it efficiently. This innovative approach holds promise for sustainable and versatile energy solutions, marking a significant step towards developing efficient and compact energy storage systems. This integration addresses the intermittent nature of solar power generation by providing a continuous and reliable power supply through energy storage. Supercapacitors are one such energy device with a high-power density and excellent specific capacitance which is integrated will a dye-sensitized solar cell (DSSC) comprising a single system of photosupercapacitor. A novel electrode material of NiO/CuO/Co3O4/rGO was synthesized which serves as the Pt-free counter electrode of DSSC and working or storage electrode of supercapacitor later was used as the intermediate electrode and storage electrode of a photosupercapacitor. The integrated photosupercapacitor device had a photovoltage of 0.81 V with arealspecific capacitance, energy and power density of 190.12 mF cm− 2, 17.325 μW h cm− 2 and 0.162 mW cm− 2, respectively. The device self-discharged in 385 s with an overall conversion efficiency of 2.17%, resulting in a self-charged energy device.

This study investigates the performance characteristics of electrodeposited (ED) silver nanowires (AgNWs) networks as transparent conducting electrodes (TCEs) considering Cu(In,Ga)Se2 (CIGS) thin-film solar cells. The electrodeposition process uniformly deposits silver onto a network of spin-coated AgNWs, resulting in the enlargement of individual nanowire diameters and the formation of stronger interconnections between the AgNWs. This structural enhancement significantly improves both the electrical conductivity and thermal stability of the ED AgNW networks, making them more efficient and robust for practical applications in solar cells. The study comprehensively examines the optoelectronic properties of the ED AgNW networks, encompassing total and specular transmittance, transmission haze values, and sheet resistance, with varying durations of silver electrodeposition. Additionally, this study presents the current density (J)-voltage (V) characteristics of CIGS thin-film solar cells employing the ED AgNW TCEs, revealing how electrodeposition duration impacts overall device performance. These findings offer valuable insights for optimizing TCEs in not only thin-film solar cells but also in other optoelectronic devices, highlighting the potential for improved long-term stability across various applications without compromising performance.

Super P (SP) is a conductive carbon black that significantly enhances the electrical conductivity of various types of electrodes, making it a widely preferred conductive agent in lithium-ion batteries. By contrast, activated carbon (AC), originally used in capacitors due to its porous structure, is expected to contribute to electrochemical performance through its enhanced interaction with lithium ions. First, the physical properties of both materials were analyzed through various characterization techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) to confirm the increase in electrochemical properties through the combination of SP and AC. Furthermore, the microstructure and electrical properties of the LiFePO4 (LFP) electrode were analyzed, to determine the impact on battery performance. With a 1.15 M LiPF6 in an ethylene carbonate/diethyl carbonate (EC/DEC) electrolyte, the results indicated that SP-only electrodes exhibited the highest conductivity and lowest surface resistance, making them the most effective at maintaining stable electrochemical performance. In contrast, electrodes with only AC showed higher resistance, demonstrating that SP remains superior in improving LFP electrode conductivity, ultimately optimizing lithium-ion battery performance.

Activated carbon has broad application prospects for treating pollutants due to its easy availability, low cost and good adsorption. In our work, nano-activated carbons (NAC) with abundant functional groups are obtained by the oxidation modification of HNO3, ( NH4)2S2O8, and KMnO4, which are used to construct the particle electrodes to degrade NDEA in a continuous flow electrochemical reactor, and the influence of relevant factors on the performance of NDEA removal is discussed. The experimental data show that the optimal degradation efficiency is 42.55% at the conditions of 3 mL/min influent water flow, 0.21 M electrolyte concentration, 10 mA/cm2 current density, and 10 μg/mL initial NDEA concentration. The degradation of NDEA conforms to a quasi second order kinetic equation. The electrocatalytic mechanism of NAC electrodes for removing NDEA is firstly discussed. The effects of different free radicals on the degradation of NDEA are also demonstrated through free radical quenching experiments, indicating that the degradation of NDEA is dominated by ⋅OH. The degradation pathway of NDEA and final products are obtained using GC–MS. NAC particle electrodes as the cheap and efficient electrocatalyst in continuous flow electrochemical reactor system provide a greener solution for the removal of disinfection by-products from drinking water.

Cu-Ti thin films were fabricated using a combinatorial sputtering system to realize highly sensitive surface acoustic wave (SAW) devices. The Cu-Ti sample library was grown with various chemical compositions and electrical resistivity, providing important information for selecting the most suitable materials for SAW devices. Considering that acoustic waves generated from piezoelectric materials are significantly affected by the resistivity and density of interdigital transducer (IDT) electrodes, three types of Cu-Ti thin films with different Cu contents were fabricated. The thickness of the Cu-Ti thin films used in the SAW-IDT electrode was fixed at 150 nm. As the Cu content of the Cu-Ti films was increased from 31.2 to 71.3 at%, the resistivity decreased from 10.5 to 5.8 × 10-5 ohm-cm, and the density increased from 5.5 to 7.3 g/cm3, respectively. A SAW device composed of Cu-Ti IDT electrodes resonated at exactly 143 MHz without frequency shifts, but the full width at half maximum (FWHM) values of the resonant frequency gradually increased as the Cu content increased. This means that although the increase in Cu content in the Cu-Ti thin film helps to improve the electrical properties of the IDT electrode, the increased density of the IDT electrode deteriorates the acoustic performance of SAW devices.

In the present study, the effects of electrodes type (copper, steel or CFRP) and design (plate or mesh) on electrical stability of conductive cement as exposed to various weathering conditions were investigated. To fabricate these composites, multiwalled carbon nanotube and carbon fiber were added to the cement composites by 0.6 and 0.4% by cement mass. Seven different types of electrodes were embedded to the samples, and their electrical stability was examined during the curing period. In addition, the fabricated samples were exposed to water ingress and cyclic heating conditions. Then, the compressive strength of the samples was evaluated to observe the interfacial bonding between the cement paste and electrodes. Based on the experimental results, it was found that the samples showed different electrical stability even their mix proportion was same. Thus, it can be concluded that the type and design of the electrodes are important in measuring the electrical properties of the conductive cement composites. Specifically, an improved electrical stability of electrodes is required when they are exposed to various weathering conditions.