Performance Supercapacitors Research Articles

Flexible supercapacitors based on in-situ synthesis of composite nickel manganite@reduced graphene oxide nanosheets cathode: An integration of high mechanical flexibility and energy storage

Supercapacitors have attracted considerable attention in the context of electric vehicles, renewable energy storage, and industrial equipment. Nevertheless, further work is required to enhance the energy storage performance and improve the adaptability of supercapacitors under mechanical loads. To address these challenges, we propose a novel design strategy for composite micro-nano structures of reduced graphene oxide coated in situ growth of nickel manganite nanoarrays on the carbon fiber surface (CF@NiMn2O4@rGO). This design enables the fabrication of flexible supercapacitor electrodes with optimised electrochemical and mechanical properties. The CF@NiMn2O4@rGO cathode exhibits a synergistic effect that enhances energy storage, as evidenced by a high specific capacitance of 1003.35 F g−1 (at 10 mA cm−2) and exceptional cycling stability over more than 4000 cycles. Furthermore, the flexible carbon fiber (CF) and in-situ grown nickel manganite@reduced graphene oxide (NiMn2O4@rGO) contribute to improved mechanical properties of the electrode. The assembled supercapacitor exhibits both high energy density and cycling stability. Notably, the flexible bending angle ranging from 0° to 180° has minimal impact on the energy storage performance of this flexible supercapacitor. Even under a bending angle of 180°, it successfully powers a small light bulb. This novel nanostructured material presents an innovative approach for designing flexible supercapacitors.

High-voltage aqueous supercapacitors enabled by polysiloxane passivation coating-modified carbon cloth electrode

The voltage window plays a crucial role in determining the energy density of supercapacitors. The limited energy density of carbon-based supercapacitors poses a significant challenge to their widespread adoption. Here, we propose a novel approach to modify carbon cloth by implementing a polysiloxane (PSiO) passivation coating. This forms an ion-conductive and electron-insulating thin film on the surface, effectively impeding electron conduction from electrode surface to electrode/electrolyte interface and suppressing electrolyte electrolysis. Consequently, an expanded voltage window is realized, thereby enhancing the energy density of aqueous carbon-based supercapacitors. The carbon cloth electrode modified with the PSiO passivation coating (CC-A-KH560) exhibits exceptional electrochemical performance, with a significantly increased 78.6 % widened applicable potential range compared to the activated carbon cloth electrode (CC-A). In a two-electrode configuration, the voltage window is broadened from 0.8 V for CC-A to 1.4 V for CC-A-KH560, and the energy density based on CC-A-KH560 is 8 times that based on CC-A. The good stability and durability are also obtained for the firm C–O–Si bonds during PSiO modification. More importantly, this design provides a generic solution of PSiO passivation coating-modified carbon electrode, applicable for diversified silicane couple agents, to realize a high-voltage energy storage performance for aqueous supercapacitors.

Harnessing the potential of Type-II heterostructures: NiO/TiO2/ZnO fibers for enhanced photocatalytic and electrochemical performance in asymmetric supercapacitors

A novel two-step approach, electrospinning followed by wet chemical route, was used for the synthesis of NiO/TiO2/ZnO heterostructure fibers. Structural, morphological, and elemental analyses confirmed the single-phase formation with a unique, one-dimensional furry insect-like morphology, free of impurities. BET analysis revealed a significant increase in the specific surface area from 12.64 to 54.50 m2/g for NiO/TiO2/ZnO heterostructure fibers, indicating the existence of more active sites for catalytic and redox activities. Optical studies demonstrated a reduction in the band gap of NiO in the presence of TiO2 and ZnO, enhancing the photocatalytic properties. The Langmuir-Hinshelwood kinetic model was employed to measure the reaction rate constant, showing improved photocatalytic performance of NiO by enhancing the separation rate of photo-generated electrons and holes on its surface. Furthermore, the electrochemical performance of the prepared fibers-based asymmetric supercapacitors (ASCs) showed a low polarization, attributed to low charge transfer resistance. The NiO/TiO2/ZnO fibers-based ASCs exhibited higher specific capacitance (108 F/g), with a maximum specific energy density of 9.6 Wh/kg at a specific power density of 2000 W/kg indicating excellent performance suitable for finding potential uses in energy storage applications. Various practical and physical tests further certified the efficient performance of the prepared NiO/TiO2/ZnO heterostructure fibers-based asymmetric supercapacitors. The contribution of NiO and TiO2 to the inner surface were ∼52.02 and ∼47.08 %, respectively. In contrast, the NiO/TiO2/ZnO fibers showed a notable difference, with ZnO-NWs contributing ∼4.99 % to the overall surface. This increase in the inner surface contribution to around 95.01 % indicates that the growth of ZnO-NWs provides additional channels for electrochemical reactions during redox processes and enhances adhesion between the ZnO-NWs and NiO/TiO2 heterostructure, facilitating OH− ions transportation.

Influence of morphological variations in cobalt bismuth oxide on supercapacitor performance

In this study, we successfully synthesized novel cobalt bismuth oxide (CBO) using various solvothermal methods. These materials were then utilized as active electrode materials for supercapacitors and photocatalysts. A variety of techniques was employed to analyse the crystal structure, morphology, and surface of the prepared samples. The morphological analysis revealed that S1 (nanosheet) and S3 (nanoneedles) are in nanostructure form. The S3 electrode demonstrated a specific capacitance of 270.9 F g-1 at a current density of 1 Ag-1, compared to the S1 electrode, which exhibited a specific capacitance of 181.7 F g-1 under the same conditions. Furthermore, when subjected to a current density of 3 A g-1, the S1 and S3 retained 79 % and 62 % of their capacitance, respectively after 2000 cycles. The morphological variations in the samples play a crucial role in capacitive performance and mechanism, characterised by a significant presence of lattice defects and oxygen vacancies.

Highly Conductive Supramolecular Salt Gel Electrolyte for Flexible Supercapacitors.

Conductive gels have greatly facilitated the development of flexible energy storage devices, including supercapacitors, batteries, and triboelectric nanogenerators. However, it is challenging for gel electrolytes to tackle the trade-off issues between mechanical properties and conductivity. Herein, a strategy of all inorganic salt-driven supramolecular networks is presented to construct gel electrolytes with high conductivity and reliable mechanical performance for flexible supercapacitors. The salt gel is successfully fabricated by combining a salt supramolecular network constructed by NH4Mo7O24·4H2O and FeCl3·6H2O and a polymer network of poly(vinyl alcohol). The inorganic salt supramolecular network serves as a rigid self-supporting framework in the hydrogel system for improving the mechanical properties and providing abundant active sites for accelerating ion transport. Furthermore, the salt gel-enabled supercapacitors are equipped and exhibit a high specific capacitance (199.4 mF cm-2) and excellent energy density (27.69 μWh cm-2). Moreover, the flexible supercapacitors not only present remarkable cyclic stability after 3000 charging/discharging cycles but also exhibit good electrochemical stability even under severe deformation conditions. The strategy of salt-gel-driven flexible supercapacitors would provide fresh thinking for the development of advanced flexible energy storage fields.

Synergistic advancements in battery-grade energy storage: Nb2C/MoTe2(PANI) hybrid electrode material as a enhanced electrocatalyst for hydrogen reduction reaction

The inherent stratified arrangement, narrow energy band gap, and similar electrical conductivity of two-dimensional (2D) molybdenum ditelluride (MoTe2) have attracted considerable interest for their use in supercapacitors. Integrating Niobium Carbide (Nb2C) into the MXene framework significantly improves self-aggregation and electrochemical activity. The current work, Nb2C/MoTe2 was synthesized via a cost-effective and simple hydrothermal technique. However, the Nb2C/MoTe2 nanocomposite shows pronounced self-stacking problems during electrode fabrication, which can significantly restrict the capacity for storing charge. PANI was incorporated as a dopant to address these challenges and enhance electrochemical activity, such as Nb2C/MoTe2(PANI). The performance of supercapacitors was assessed by electrochemical measurement in an aqueous electrolytic solution with a concentration of 2 M potassium hydroxide (KOH). Based on the GCD profile, the Nb2C/MoTe2(PANI) material demonstrates a notable specific capacity (Qs) of 270 C/g, energy density of 72.2 Wh/kg, and power density of 935 W/kg at a current density of 2 A g-1. In contrast, the composite material demonstrates a specific capacity of 185 C/g, as proven by CV conducted at 5 mV/s. In addition, the nanohybrid has a high level of capacitance retention of 87.6 % after undergoing 8500 consecutive cycles. The exceptional efficiency of supercapacitor applications can be ascribed to the enhanced mechanical flexibility, active cooperation, and synergistic impacts of Nb2C/MoTe2 and PANI. The Nb2C/MoTe2(PANI) nanocomposite possesses significant potential for eco-friendly energy generation and allows for a simple single-step fabrication procedure. Consequently, it can serve as an electrode for highly efficient supercapacitors.

MOF-on-MOF Derived Co2P/Ni2P Heterostructures for High-Performance Supercapacitors.

Metal-organic frameworks (MOFs) have been widely used as versatile precursors to fabricate functional nanomaterials with well-defined structures for various applications. Herein, the presynthesized Ni-MOF nanosheets were grown on a Ni foam (NF) substrate, which then guided the nucleation and further growth of Prussian blue analogues (PBA) nanocubes to form MOF-on-MOF of the PBA/Ni-MOF film. This film was subsequently converted into a Co2P/Ni2P heterostructure. The NF-supported Co2P/Ni2P composites exhibited excellent supercapacitor performance, delivering a high specific capacity of 5124.2 mF cm-2 at 1 mA cm-2 and a remarkable capacity retention of 80.69% after 3000 cycles at 10 mA cm-2. An asymmetric supercapacitor assembled using Co2P/Ni2P/NF as the cathode and activated carbon as the anode yielded a maximum energy density of 0.34 mWh cm-2 at a power density of 1.50 mW cm-2. The enhanced supercapacitor performance is attributed to the synergistic effects of the Ni2P and Co2P components with multiple valence states as well as the unique hierarchical structure, which provides efficient pathways for electron and ion transport while mitigating volume expansion during energy storage. This synthetic strategy demonstrates an effective approach to fabricate phosphide-based hybrid materials for high-performance supercapacitor applications.

Development of surface-activated La0.6Ca0.4MnO3 perovskite-type electrodes using oxygen plasma for highly stable supercapacitor application

This study introduces a novel and efficient approach for synthesizing perovskite-type nanoparticles and advanced plasma surface activation to significantly improve the supercapacitor's performance. High-purity La0.6Ca0.4MnO3 (LCMO) perovskite nanoparticles with a crystalline structure were synthesized using a facile coprecipitation technique, followed by an innovative low-pressure DC glow-discharge plasma treatment in an oxygen atmosphere. This plasma surface activation process enhances the surface properties of the nanoparticles and boosts their electrochemical performance, representing a transformative modification method for energy storage materials. Detailed analysis of the synthesized and surface-activated LCMO (SA@LCMO) nanoparticles revealed a well-defined cubic morphology with a remarkable surface area of 95 m2/g, as confirmed by TEM and BET analysis. The plasma-treated SA@LCMO electrodes demonstrated superior supercapacitor performance, delivering an impressive specific capacitance of 453 F/g at a current density of 1 A/g more than doubling the 225.8 F/g achieved by untreated LCMO electrodes. Additionally, the SA@LCMO electrodes exhibited exceptional cycle stability, retaining 87 % of their capacitance and achieving a coulombic efficiency of 95.2 % after 10,000 GCD cycles. The material also showed promising energy storage capabilities, with a maximum energy density of 3.92 Wh/kg at a power density of 170.6 W/kg. These results highlight the transformative impact of plasma surface activation on perovskite nanomaterials, positioning the SA@LCMO as a highly promising candidate for next-generation energy storage technologies with superior energy density, durability, and performance. This study introduces new avenues for surface engineering perovskite-based materials to create scalable high-performance energy storage devices.

Design and fabrication of Bi2S3/Gr composite materials for investigating the performance of hybrid supercapacitors as advanced battery-type electrodes

Design and fabrication of Bi2S3/Gr composite materials for investigating the performance of hybrid supercapacitors as advanced battery-type electrodes

Microstructural Regulation of Co TCPP by Acetylene Black: Enhanced Electrochemical Performance for Wearable Supercapacitors

Abstract With the rapid development of wearable devices, flexible supercapacitors have become an important energy storage prototype due to their inherent flexibility and high power density. Two-dimensional metal-organic framework (2D MOF) nanosheets are widely used in energy storage systems due to their structural tunability and anisotropy. However, their high surface energy tends to lead to aggregation, which results in poor dispersion and rheology of formulated inks and inhomogeneity of printed electrodes. Existing methods involve surface modulation by capped organic ligands, yet ignore the inherent conductivity and stability of MOFs. To overcome the low conductivity and aggregation problems of 2D MOFs, we adopted a novel approach combining mechanical intercalation and surface functionalization of cobalt-based porphyrin frameworks (Co TCPP) with acetylene black (AB). The unique microstructure of the composite material leads to favorable changes in the electronic properties of AB, which reduces the overall internal resistance and promotes rapid charge transfer. For this purpose, we have prepared micro-supercapacitors (MSCs) using dispensing printing technology. This integrated material has excellent mechanical flexibility and maintains 92% specific capacitance even under extreme bending and torsion. This study highlights the potential of integrating 2D MOFs with carbon-based materials (e.g., acetylene black) for a variety of applications in wearable electronics, and provides a guiding scheme for future micro-modulation of 2D MOFs using conductive materials.

Tip effect of NiCo-LDH with low crystallinity for enhanced energy storage performance of yarn-shaped supercapacitors

Layered double hydroxides (LDHs) are considered promising materials for supercapacitor applications. However, the development of yarn-shaped supercapacitors (YSCs) with high electrochemical performance utilizing LDHs remains challenging. In this study, the NiCo-LDHs with various morphologies (nano-needles, nano-sheets, needle-sheet composites, and nano-flowers) were grown on carbon nanotubes (CNTs)-functionalized cotton yarn via a co-precipitation technique for YSC applications. Among these, the yarn incorporating nano-needle NiCo-LDHs exhibited reduced crystallinity yet demonstrated a superior areal capacitance compared to other morphologies, following a diffusion-controlled process. Finite element simulations were subsequently conducted to investigate this phenomenon, revealing that the lower-crystallinity nano-needle NiCo-LDHs accumulated a greater charge at their tips, thereby enhancing redox reactions and achieving higher energy storage capacitance. Subsequently, the yarns with nano-needle NiCo-LDHs were assembled into flexible quasi-solid-state symmetric YSCs, achieving a peak areal capacitance of 124.27 mF cm−2 and an exceptionally high energy density of 39.4 μWh cm−2 at a current density of 0.2 mA cm−2. Furthermore, our YSCs can be scaled up through serial or parallel connections and integrated into fabrics, making them suitable for wearable energy storage applications. This work provides an efficient method for fabricating high-performance YSCs and demonstrates significant potential for wearable energy storage devices.

Influence of Phosphoric Acid Activation on Physiochemical Characteristics of Activated Carbons and Their Performance as Supercapacitor

ABSTRACTWe investigate the influence of phosphoric acid (H3PO4) activation on physiochemical characteristics of activated carbons (ACs) as a function of number of activation steps such as two‐step and three‐step and impregnation ratio (IR). Scanning electron microscopy observations identified that different morphologies in the forms of graphene sheet‐like, nano‐granular, and flake‐like carbon structure in the cases of ACs. FTIR spectroscopy confirmed that successful incorporation of phosphorous group in the ACs by H3PO4 activation. X‐ray diffraction (XRD) profile exposed that irrespective of the activation method and IR, all AC samples showed narrow and sharp XRD crystalline peak along with the amorphous signals. Raman scattering analysis suggested that three‐step activation create more defective structure as compared to two‐step activation route. Nitrogen adsorption–desorption isotherm measurements indicated that upon fabricating ACs via three‐step and two‐step activation approach, around 6.5 times and 3‐fold enhancement in the value of surface area of ACs as compared to that of carbon before activation. In addition, higher the IR value, lower the textural properties of ACs. This study demonstrated that three‐step activation methodology is capable of generating highly porous AC when compared to two‐step activation route. Cyclic voltammetry analysis showed that for the electrode developed from AC that fabricated via three‐step activation, capacitance retention of 50% is achieved upon tuning the scan rate by 10 times. The same electrode exhibited the capacitance retention of 45% upon increasing the current density by 10 times. We have also compared the electrochemical performance of symmetric and asymmetric supercapacitors. Electrochemical capacitance retention of symmetric and asymmetric supercapacitors is determined to be 100% and 92% respectively after 1000 cycles at the current density of 1 A g−1. Based on the Ragone plot study, it is observed that the maximum energy density of 5 W h kg−1 and the maximum power density of 943 W kg−1 are attained for the case of symmetric supercapacitors. Asymmetric supercapacitor displayed improved energy density of 7.15 W h kg−1 and modest power density of 432 W kg−1.

Plasma assisted single-step synthesis of carbon-coated SrFe2O4 electrodes for enhancing supercapacitor and oxygen evolution reaction

Developing highly efficient, conductive, and porous electrode materials for superior electrochemical bifunctional applications presents a formidable challenge, particularly when considering impurity-free large-scale production. This investigation focuses on synthesizing a composite material of highly conductive amorphous carbon-coated SrFe2O4 nanoparticles to enhance supercapacitor and oxygen evolution performance. The C@SrFe2O4 nanoparticles were synthesized through a thermal plasma process utilizing argon, methane, and carbon dioxide gas environments. The prepared samples' phase, crystal structure, morphology, elemental composition, and chemical state analysis were thoroughly examined. The electrochemical performance of the prepared samples, including Fe3O4, SrO, and C@SrFe2O4 electrodes, was evaluated for their suitability in electrochemical capacitor applications. Remarkably, C@SrFe2O4 nanoparticles exhibited notable electrochemical pseudocapacitive behavior, demonstrating a significantly higher specific capacitance of 588.7 F/g at a current density of 1 A/g. Moreover, at a current density of 10 A/g, the C@SrFe2O4 electrode exhibited outstanding cycling stability, maintaining 91 % of its initial capacitance over 5000 charge-discharge cycles. Furthermore, it showcased exceptional and uniform electrocatalytic activity for the OER, requiring only 186 mV in overpotentials to achieve a current density of 10 mA/ cm2. These findings underscore the potential of mesoporous C@SrFe2O4 nanoparticles as promising materials for supercapacitors and OER applications.

Microwave-assisted hydrothermal synthesis of αβ-Ni(OH)2 nanoflowers on nickel foam for ultra-stable electrodes of supercapacitors

Transition metal hydroxides (TMHs) are considered promising materials for supercapacitors because of their high theoretical capacitance and tunable morphology. Among TMHs, nickel hydroxide stands out for its multiple oxidation states, facilitating charge storage. This paper reports on a novel microwave-assisted hydrothermal technique employed to synthesize mixed-phase nickel hydroxide nanoflowers directly at the surface of nickel foam substrates with improved electrochemical stability compared to pure phases of nickel hydroxide. The analysis of nickel hydroxide in different phases alpha, beta and mixed-phase materials using physiochemical techniques like XRD, SEM, EDX, RAMAN, FT-IR and TGA is explained. The areal capacitance calculated from GCD tests for α-Ni(OH)2, β-Ni(OH)2 and αβ-Ni(OH)2 is estimated 7.35 F/cm2, 2.66 F/cm2 and 5.12 F/cm2 at a current density of 10 mAcm−2. The mass-specific capacitance calculated from GCD tests for α-Ni(OH)2, β-Ni(OH)2 and αβ-Ni(OH)2 is estimated 2311 Fg−1, 688 Fg−1 and 1511 Fg−1 at a current density of 10 mAcm−2. The cyclic stability test revealed the superior cycling performance of nickel hydroxide in mixed-phase as the cathode of an ultralong supercapacitor with nearly 100% capacitance retention after 5000 cycles at 50 mAcm−2. The proposed synthesis technique advances the efficiency and control of nanostructure geometry, providing insights into the design for electrodes of extreme-performance supercapacitors. However, conventional synthesis methods are time-consuming and energy-intensive. These findings underscore the potential of mixed-phase nickel hydroxide as an outstanding electrode material with extended cyclic performance for supercapacitors, contributing to the improvement of energy storage technologies in the renewable energy landscape.

The relationship between the high-frequency performance of supercapacitors and the type of doped nitrogen in the carbon electrode

Nitrogen doping has been widely used to improve the performance of carbon electrodes in supercapacitors, particularly in terms of their high-frequency response. However, the charge storage and electrolyte ion response mechanisms of different nitrogen dopants at high frequencies are still unclear. In this study, melamine foam carbons with different configurations of surface-doped N were formed by gradient carbonization, and the effects of the configurations on the high-frequency response behavior of the supercapacitors were analyzed. Using a combination of experiments and first-principle calculations, we found that pyrrolic N, characterized by a higher adsorption energy, increases the charge storage capacity of the electrode at high frequencies. On the other hand, graphitic N, with a lower adsorption energy, increases the speed of ion response. We propose the use of adsorption energy as a practical descriptor for electrode/electrolyte design in high-frequency applications, offering a more universal approach for improving the performance of N-doped carbon materials in supercapacitors

Impressive electrochemical characteristics of freeze-dried nanosheet structured Mn2P2O7 for affordable electrochemical capacitor

The electrochemical capacitive performance of supercapacitors (SCs) is mainly evaluated by active electrode material, which plays a critical participation. At present, transitional metallic pyrophosphates (TMPs) have grabbed more interest as active electrodes in SC configuration. In this work scenario, we informed a novel strategic synthesis route for constructing Mn2P2O7 (MP) through an ultrasonic probe-assisted chemical reaction approach. The electrode in the form of a monoclinic, freeze-dried nanosheet structure characterized by XRD, FESEM- TEM, and its signature chemical bonds and chemical composition were confirmed via FTIR and EDS analysis, respectively. As prepared active sample was successfully sent into electrochemical investigation tools such as Cyclic Voltagrams (CV), Galvanostatic charge/discharge (GCD), electrochemical impedance analysis (EIS), and Cycling life span (stability) using three and two-electrode set-up. These tests indicate that the active sample holds an impressive capacitive value of 558 F/g at scanning range of 2 mV/s, a specific capacity of 420 C/g at 1 A g-1, magnificent rate capability, 90 % retention over 10,000 successive voltammograms in three-electrode measurements. Additionally, the fabricated symmetric supercapacitor device shows superior energy density, power density, and good rate capability in two electrode investigations. The mentioned prominent results reflect that engineered MP and its characteristics are the efficient fruits in manufacturing affordable electrochemical capacitors.

Two-step hydrothermal synthesis of hydrangea-like Bi2O2Se with high performance for supercapacitors

The hydrangea-like structure of Bi2O2Se, composed of ultra-thin nanosheets, was prepared by a 2-step hydrothermal method for supercapacitor applications. The unique hydrangea-like structure of Bi2O2Se, characterized by a substantial specific surface area and abundant pore morphologies, facilitated the infiltration of electrolyte. The presence of bismuth vacancies not only enhanced the conductivity, but also increased the spacing between [Bi2O2]n2n+ and [Se]n2n– layers, creating room for K+ insertion/extraction and augmenting the surface-controlled pseudo-capacitance. Consequently, the hydrangea-like Bi2O2Se exhibited a high specific capacitance of 650 F/g at 1 A/g, excellent rate capability of 62 % from 1–20 A/g, and retained 80 % of its initial capacitance after 2000 cycles.

Enhancement of energy storage performance of supercapacitors based on MoS2-g-C3N4 Nanocomposite electrodes

Enhancement of energy storage performance of supercapacitors based on MoS2-g-C3N4 Nanocomposite electrodes

Enhanced Electrochemical Performance of NiMn Layered Double Hydroxides/Graphene Oxide Composites Synthesized by One-Step Hydrothermal Method for Supercapacitors.

This study aims to enhance the performance of supercapacitors, focusing particularly on optimizing electrode materials. While pure NiMn layered double hydroxides (LDHs) exhibit excellent electrochemical properties, they have limitations in achieving high specific capacitance. Therefore, this paper successfully synthesized composite materials of NiMn LDHs with varying loadings of graphene oxide (GO) using a hydrothermal method. Systematic physicochemical characterization of the synthesized materials, such as powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), and Raman spectroscopy, revealed the influence of GO doping on the microstructure and electrochemical performance of NiMn LDHs. Electrochemical tests demonstrated that the NiMn LDHs/GO electrode material exhibited optimal electrochemical performance with a specific capacitance of 2096 F g-1 at 1 A g-1 current density and 1471 F g-1 at 10 A g-1, when GO doping level was 0.45 wt %. Furthermore, after 1000 cycles of stability testing, the material retained 53.3 % capacitance at 5 A g-1, indicating good cyclic stability. This study not only provides new directions for research on supercapacitor electrode materials but also offers new strategies for developing low-cost and efficient electrode materials.

NiMn-Ag NWs complexes electrode material with in situ grown conductive 3D networks for enhanced supercapacitive performance by boosting Ni2+

Power density is one of the important factors affecting the performance of electrode materials, which is hampered by ion/electron transport and agglomeration build-up problems. In this study, a novel 3D NiMnO3/Ni(OH)2/Ag NWs composite is synthesized via the introduction of Ag NWs. The introduction of Ag NWs synergistically influences the crystal structure and micro-morphology of the NiMnO3/Ni(OH)2/Ag NWs composite. The unique pentatwinned structure of Ag NWs facilitates the enhancement of the (110) and (101) crystal planes, which induces the movement of Ni 2p3/2, leading to a significant increase of Ni2+ concentration in the composites. This ensures an abundance of ion adsorption sites, generating materials conducive to reactive activity. This new structure increases the density of active sites and establishes a conductive network, which optimizes the electron and ion transport paths, greatly reduces the diffusion resistance at the electrode-electrolyte interface, and improves the charge transfer efficiency, thus effectively increasing the specific capacity and energy density of the material. The NiMnO3/Ni(OH)2/Ag NWs//AC device exhibits a remarkable specific capacity of 350.478 mAh·g−1 at a current density of 0.01 A cm−2, and its Ragone plot reveals a peak energy density of 81.107 Wh kg−1 at a power density of 1699.871 W kg−1. Additionally, it achieves an energy density of 60.532 Wh kg−1 at a power density of 8490.072 W kg−1. This study explores the design and application of 3D structured electrode materials, which effectively improves the specific capacity of the materials and provides a new idea to further improve the energy density of supercapacitors.