Electrode Materials For Supercapacitors Research Articles

Harnessing dysprosium telluride/GPE as an effective electrode for energy storage and conversion

Hydrogen stands out as a clean alternative to fossil fuels, and its production via water electrolysis is promising, although the slow kinetics of the oxygen evolution reaction (OER) pose a significant challenge. Alongside energy conversion, the quest for effective energy storage remains critical. This study explores the potential of dysprosium telluride (Dy2Te3) as a highly efficient catalyst for OER and a supercapacitor electrode. The hydrothermally synthesized Dy2Te3 exhibits exceptional OER activity, characterized by an overpotential of 294 mV at 1.48 V vs. RHE, a low Tafel slope of 48 mV dec−1, and minimal interfacial resistance of 13 Ω. In a 1.0 M KOH solution, Dy2Te3 nanoparticles demonstrate outstanding supercapacitor performance, achieving a power density of 283.5 W kg−1, specific capacitance of 645.33 F g−1, and energy density of 22.8 Wh kg−1 at 1 A g−1. The high performance is attributed to enhanced electrical conductivity and a low impedance of 0.352 Ω in a three-electrode system. In a practical two-electrode configuration, Dy2Te3 nanoparticles deliver a specific capacitance of 479 F g−1, energy density of 94 Wh kg−1, and power density of 0.32 kW kg−1, with a reduced interfacial resistance of 1.03 Ω. These results underscore the potential of Dy2Te3 as a viable electrode material for both supercapacitors and water splitting, offering valuable insights into the application of lanthanide-based metal chalcogenides in energy technologies.

Unveiling the potential: Asymmetric supercapacitors with conductive polymers/Ti3C2Tx/Ni3S4 electrodes deliver high energy densities

Ti3C2Tx is considered a promising electrode material for supercapacitors due to its fast electronic properties, excellent hydrophilicity and mechanical properties. However, severe Ti3C2Tx nanosheet stacking reduces the exposed active sites and hinders the ion diffusion of Ti3C2Tx, leading to poor electrochemical performance. Here, we report a strategy for doping of Ti3C2Tx, in which the Ni3S4 and conducting polymer (CP) were selected as doping agent for Ti3C2Tx, and it is expected that metal sulfide and CP can overcome the defects of Ti3C2Tx. In this work, the conducting polymers were as polyaniline (PANI), polypyrrole (PPY) and poly(3,4-ethylenedioxythiophene) (PEDOT). As a result, the prepared composites exhibit superior multiplicative capacity with a capacitance of 2502 F g-1 (PANI/Ti3C2Tx/Ni3S4), 2440 F g-1 (PPY/Ti3C2Tx/Ni3S4), and 2620 F g-1 (PEDOT/Ti3C2Tx/Ni3S4), respectively. In addition, CP/Ti3C2Tx/Ni3S4// AC asymmetric supercapacitors were assembled with energy densities of 60.2 (PANI/Ti3C2Tx/Ni3S4), 86.7 (PPY/Ti3C2Tx/Ni3S4), and 53.4 (PEDOT/Ti3C2Tx//Ni3S4) Wh kg-1 at 1,500 W kg-1, respectively. This work develops a simple way to prepare the porous Ti3C2Tx film for supercapacitors with excellent electrochemical performance.

Vacancy Engineering of Selenium-Vacant NiCo2Se4 with Enhanced Electrochemical Performance for Supercapacitor.

Vacancy engineering effectively modulates the electronic properties of electrode materials, thereby improving their electrochemical performance. In this study, we prepared selenium-deficient NiCo2Se4 (Sev-NCS) using ethylene glycol as a reducing agent in NaOH alkaline environment, and investigated its potential as an electrode material for supercapacitors. Both theoretical and experimental results confirmed that the introduction of vacancies altered the morphology and electronic structure of NiCo2Se4, which in turn synergistically improved the conductivity and the diffusion capability of electrolyte ions. The optimized Sev-NCS electrode achieved an excellent specific capacitance of 2962.7 F g-1 at a current density of 1 A g-1 and superior cycling stability with a capacitance retention of 89.5% even after 10,000 cycles. Furthermore, an asymmetric device composed of the optimized Sev-NCS electrode as the positive electrode and activated carbon as the negative electrode achieved an energy density of 55.6 Wh kg-1 at a power density of 800 W kg-1. Therefore, this work offers novel insights into the role of vacancy engineering in improving the performance of transition metal compound-based electrode materials for supercapacitor.

Two-step cathodic microwave electrodeposition for construction of Co9S3(OH)5@Ni(OH)2 hetero-structure as supercapacitor electrode materials

The preparation of two-phase electrode materials of Co9S8@Ni(OH)2 typically involves a laborious three-step process. In this study, a two-step cathode microwave electrochemical method was proposed for the fabrication of Co9S8@Ni(OH)2 electrode materials for supercapacitors, eliminating the need for precursor synthesis. This approach not only simplified the preparation process and saved time but also successfully produced a p-n heterostructure electrode material consisting of Co9S8@Ni(OH)2 phases, where the Co9S8 phase has a chemical formula of Co9S3(OH)5. This unique structure is capable of inducing an internal electrical field by facilitating the transfer of charge carriers from Co9S3(OH)5 to Ni(OH)2, thereby enhancing charge transfer kinetics. As a result, the electrode exhibited remarkable supercapacitive performance, achieving a high specific capacitance of 255.4 mAh g-1 (7.56 F cm-2) at 1 A g-1. Even at a 20-fold increase in charge/discharge current density, the specific capacitance remained high at 218.9 mAh g-1 (6.48 F cm-1), retaining 85.8 % of the initial capacity. Furthermore, the Co9S3(OH)6@Ni(OH)2 electrode materials demonstrated excellent durability, enduring 10000 cycles with a capacitance retention of 92.9 % of the initial value. An asymmetric supercapacitor constructed with Co9S3(OH)5@Ni(OH)2 as the anode and a commercial active carbon film as the cathode was able to power a red light diode continuously emitting light for up to 42 min.

Synthesis and investigation of charge storage characteristics in Ni-MOF/PANI composite as an active electrode material for supercapacitor

This study aimed to develop a more stable and efficient energy storage device, synthesis of nickel-based pristine metal organic framework (MOF) and combined it with the emeraldine base phase of polyaniline (PANI) which is confirmed with XRD, SEM and TEM. Both Ni-MOF and PANI exhibit faradaic (battery-like) behaviour. However, when these two materials are combined, the stability of the resulting material is enhanced. The initial materials, MOF and PANI, exhibit specific capacities of 42 C/g and 72 C/g, respectively. However, when these two materials are combined, their composite exhibits an enhanced specific capacity of 122 C/g. The cyclic voltammetry (CV) analysis shows oxidation and reduction peaks, indicating faradaic behaviour. This behaviour is further confirmed by electrochemical impedance spectroscopy (EIS). Upon comparing it with prior results, the specific capacity appears to be slightly lower. However, it is anticipated to exhibit stronger stability, which is contradictory. The composite material (Ni-MOF/PANI) exhibits remarkable capacitive retention of 99.25 % even after undergoing 5000 cycles, as anticipated. In order to validate the aforementioned findings and determine the extent of the current contribution from capacitive and diffusive control, Dunn's model was employed. The data demonstrates the prevalence of diffusive-controlled (faradaic) current over capacitive current. The highest proportion of current resulting from diffusion is 96 %, achieved at a scan rate of 5 mV/s. The highest proportion of current resulting from capacitance is 24 %, achieved at a scan rate of 300 mV/s. At lower scan rates, the material exhibits a greater faradaic behaviour, whereas at higher scan rates, there is a progressive increase in non-faradaic processes. The insufficient time for diffusive process at higher scan rates is the cause. The Dunn's model with quadratic correction is also performed and comparative results were shown. Overall, the material exhibits more stability and dominance in the faradaic process, which paves the path for improved performance.

Synthesis of rice husk derived porous carbon as low-cost and high-performance electrode material for supercapacitors

Porous carbon electrode materials derived from agricultural by-products of food processing have attracted widespread interest. Rice husk (RH) is a promising raw material owing to its abundance and low price. In this study, a supercapacitor electrode was prepared by using recycled RH and secondarily activated with ZnCl2 to enhance its electrochemical energy storage performance. RH carbonized at the optimum temperature (i.e., 800 °C) was activated to synthesize RH-800-X (X = 1, 2, 3, 4, or 5, representing the mass ratio of ZnCl2 to RH-800). Sample RH-800-3 exhibited the highest specific surface area (1348.29 m2 g−1) and mesoporous pore volume (0.8375 cm3 g−1) among the samples. In a three-electrode system, the prepared electrodes delivered a high specific capacitance (242 F g−1 at 0.3 A g−1 in 6 M KOH solution). Furthermore, the capacitance retention of RH-800-3 remained at 99.9 % after 17,000 charge/discharge cycles. The results demonstrate the excellent capacitive behavior and superior electrochemical performance of RH-800-3. In addition, symmetrical capacitors prepared using RH-800-3 have an energy density of up to 101 Wh kg−1 at a power density of 900 W kg−1. Therefore, this study presents a simple and effective method for preparing a high-performance electrode material from biomass-derived porous carbon (i.e., recycled RH) and offers a new perspective for the efficient utilization of waste biomass resources.

Potential difference-induced electrodeposition of defect-rich α-cobalt hydroxide on porous copper (PCu): High-voltage performance of supercapacitor

Designing electrode materials for aqueous battery-type supercapacitors to extend the operating voltage window remains a significant challenge to increase the energy density of aqueous supercapacitors. In this work, a directional electrodeposition method without any additives was employed to deposit α-Co(OH)2 onto a porous copper (PCu) current collector substrate, which involves the fabrication of a supercapacitor electrode material with a cross-linked network structure named α-Co(OH)2@PCu900. The potential difference between copper and cobalt facilitated the formation of a larger interlayer spacing for α-Co(OH)2. In addition, crystals of α-Co(OH)2 with different orientations exert stress on one another, leading to lattice distortion and vacancy formation. The morphology and microstructure of materials were analyzed through techniques such as SEM, HRTEM, XRD, and XPS, confirming the validity of the experimental design. This defect-rich, large interlayer spacing structure facilitates ion intercalation and deintercalation during the charge-discharge process, thereby expanding the operating voltage window. In a three-electrode system, α-Co(OH)2@PCu900 exhibited a potential range from −0.45 V to 0.55 V and demonstrated an areal capacitance of 2580 mF cm−2 and specific capacitance of 600 A g−1 at 2 mA cm−2. The α-Co(OH)2@PCu900 was used as the cathode material and commercial reduced graphene oxide (rGO) was used as the anode material in an asymmetric supercapacitor, and the ASC device exhibited an areal capacitance of 295.3 mF cm−2 and a specific capacitance of 87.89 F g−1. Notably, it retained a high energy density of 0.12 mW h cm−2 (35.27 Wh kg−1) at a power density of 1.7 mW cm−2 (505.95 W kg−1). This method established α-Co(OH)2@PCu900 as a promising supercapacitor electrode material, providing a viable strategy for designing and fabricating functional electrode materials.

Enhancing quantum capacitance in BNyne/Graphene heterostructures through transition-metal dopants for high-performance supercapacitors

Using Density functional theory (DFT), we investigated the charge storage capacity, quantum capacitance (CQ), geometry and electronic structures of BNyne/graphene heterostructures (BNyneGHs), as well as the impact of transition-metal dopants on their CQ. Our results showed that doping was more effective than vacancy defects in improving the CQ of BNyneGHs. Ti-doped BNyneGHs exhibited the highest CQ value of 360.08 μF/cm2, making them ideal positive electrode materials for supercapacitors (SCs). The presence of doping agents was found to enhance the density of states (DOS) around the Fermi level, resulting in improved CQ. Our calculations identified potential cathode or anode materials for high-energy-density SCs, providing theoretical support for the design of high-capacitance SCs.

High rate capability and ultra‐long cycling life: Electrochemical synthesis of PEDOT based electrode material doped with AMPS and its supercapacitor application

AbstractPoly(3,4‐ethylene dioxythiophene) (PEDOT) is a conducting polymer that can be used in flexible bioelectronic devices. The electrode/electrolyte interface interaction is one of the most important factors in improving the electrochemical performance of energy storage materials, and these polymers are often combined with a negatively charged poly(styrene sulfonate) (PSS) chain to improve their interaction with alkali metal cations such as sodium and potassium. In this work, we performed a one‐step electrochemical synthesis of PEDOT on carbon fabric using the molecule 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid (AMPS) to create highly effective materials for supercapacitor electrodes. The electrode had a significant increase in capacitance value, measured 16.4 times higher than that of the PEDOT electrode. The 2‐electrode system exhibited a specific capacitance value of 495.2 F g−1 at a scan rate of 5 mV s−1. It exhibited a high operating voltage of 2.3 V in aqueous electrolyte system. It showed a significant energy density of 109.0 Wh kg−1 when operating at 6.1 kW kg−1 power density and 85.2 Wh kg−1 when operating at 30.6 kW kg−1 power density. Recent findings reveal that the capacitance retention performance value of the device increased significantly to 113.9% after 25,000 cycles in 3.0 M NaCl aqueous electrolyte, demonstrating its outstanding long‐term durability. Thus, the creation of the synthesized supercapacitor electrode is a significant advance in the study of conducting polymers, which often have a limited lifetime in real‐world electronic applications.

Marigold flower-like structured battery-type Cu2O/Co(OH)2 composite electrode material for high-performance supercapacitors

Addressing the limitations of individual Cu2O and Co(OH)2 components, this study aims to develop a high-performance supercapacitor electrode by synergistically combining these materials. A composite electrode material of Cu2O/Co(OH)2 was effectively synthesized on nickel foam via a facile hydrothermal method for supercapacitor applications. The as-fabricated Cu2O/Co(OH)2 composite electrode exhibits a hierarchical marigold flower-like morphology that comprises of many interspersed nanoflakes. This unique morphology offers several advantages, including increased surface area, abundant electroactive sites, and enhanced electrolyte accessibility, all of which contribute to superior electrochemical performance. The Cu2O/Co(OH)2 electrode demonstrates exceptional battery-type supercapacitor behavior, characterized by prominent redox peaks in cyclic voltammetry curves and a well-defined potential plateau during galvanostatic charge-discharge measurements. The electrode delivers an outstanding specific capacitance of 90.21 mA h g⁻1 at a current density of 1.25 A g⁻1 and retains a remarkable 81.91 % capacitance at a high current density of 12.5 A g⁻1. Furthermore, the electrode exhibits impressive cycling stability, maintaining approximately 107.84 % of its initial specific capacity value after 200 cycles at 7.5 A g⁻1. Electrochemical impedance spectroscopy measurements reveal low solution resistance and charge-transfer resistance, signifying efficient charge-transfer kinetics within the electrode. These findings highlight the potential of Cu2O/Co(OH)2 composite electrodes as promising candidates for high-performance supercapacitor applications.

Metal-organic framework derived porous nanosheets-like Co3O4 electrodes on stainless steel with high-performance for supercapacitors

In this work, three-dimensional (3D) nanoporous MOF-derived Co3O4 was successfully prepared by a facile, easy, and rapid solvothermal method on a stainless steel substrate using 1, 4-BDC organic linker and a precursor. Additionally, the effects of the Co-precursor and organic linker on the structure, composition, and morphology of the prepared MOF-derived Co3O4 samples were investigated through an XRD study, which indicated that the MOF-derived Co3O4 thin films exhibited crystalline nature upon deposition on the stainless steel substrate. FE-SEM revealed a porous nanosheet-like morphology. EDAX analysis confirmed the formation of the MOF-derived Co3O4 structure, indicating the presence of cobalt, oxygen, and carbon elements. The oxidation states of the prepared MOF-derived Co3O4 thin films were determined by X-ray photoelectron spectroscopy. Furthermore, the electrochemical performance of the MOF-derived Co3O4 samples was evaluated in a three-electrode system using 1 M KOH electrolyte. Consequently, optimized MOF-derived Co3O4 exhibited excellent electrochemical performance attributed to these advantages. The C3 sample demonstrated an outstanding specific capacitance of 1210 F/g at a current density of 0.5 mA/cm², along with remarkable cyclic stability retention of 94.30 % after 4000 charging/discharging cycles. Additionally, the MOF-derived Co3O4 (C3) electrode showed an excellent energy density of 35.70 Wh/kg and a power density of 4.5 kW/kg. As a result, the unique hierarchical porous structure of MOF-derived Co3O4 also offers effective pathways and excellent electrochemical performance, making it a promising candidate for advanced electrode materials in high-performance supercapacitors.

Effects of Co-doping on the microstructure and electrochemical performance of nickel vanadate (Ni3V2O8) electrode material for aqueous symmetric supercapacitor

Recently, there has been an increased focus on supercapacitors due to their reliable electrochemical energy storage capabilities. This study utilized an environmentally friendly facile hydrothermal method to prepare the nickel vanadate (NiVO) and cobalt-doped nickel vanadate (Co-doped Ni3V2O8) composite for supercapacitor applications. The prepared materials of pure and Co-doped Ni3V2O8 with different concentrations of Co (10 % and 15 %) were evaluated through three electrode assemblies. It is significant to note that although Co smoothed the surface of NiVO, most of the nickel vanadate crystals broke apart into tiny particles and increased the number of electroactive sites. Pure NiVO has a specific capacitance (Cs) of 1638.06 F/g at 5 mV/s. It has been observed that the electrochemical performance has been improved by adding Co 10 % and 15 % in NiVO. The 15 % Co-doped NiVO exhibits an outstanding Cs of 2641.99 F/g at a scan rate of 5 mV/s with a high capacitance retention of 98.14 % after 1k charge-discharges cycles. This excellent performance of the material is due to more electroactive sites and synergistic effects among Co and Ni in the composite. To further elaborate the electrochemical performance of 15 % Co-doped NiVO, it is employed for the fabrication of a symmetries supercapacitor (SSC) device, which shows that the fabricated device has a capacitance of 286 F/g at a current density (CD) of 0.5 A/g and high energy density of 39.7 Wh/kg at a power density of 333.33 W/kg. The symmetric device maintains a cyclic stability of 93.8 % while undergoing 5000 consecutive charge–discharge cycles at a current density of 10 A/g. Based on rigorous testing and analysis, these findings suggest that the prepared electrode material is reliable and suitable for implementation in forthcoming wearable electronic systems.

Activated carbon-supported LaNiO3 perovskite nanocomposite supercapacitor electrode material exhibiting superior power density and life cycle

Activated carbon-supported LaNiO3 perovskite nanocomposite supercapacitor electrode material exhibiting superior power density and life cycle

Affordable Two-Dimensional Layered Cd(II) Coordination Polymer: High-Performance Pseudocapacitor Electrode Behavior.

In recent years, pseudocapacitive materials have been investigated rigorously as they provide a unique pathway for realizing high-energy and high-power densities. However, innovative approaches involving rational design and synthesis of new materials are still vital to address concerns such as degradation, low conductivity, low cycling performance, high resistance, production cost, etc. Working in this direction, we report the cost-effective synthesis, characterization, and excellent pseudocapacitive behavior of a Cd(II)-based coordination polymer (COP) abbreviated as Cd(DAB). It has been realized in quantitative yield through a facile one-pot reaction occurring among the N4-ligand, 3,3'-diaminobenzidine (DAB), and Cd(II) ions, derived from Cd(OAc)2·2H2O, at room temperature. The proposed structure of the COP was ascertained by subjecting it to various standard spectroscopic and electron microscopic studies; these techniques reveal the self-assembly of indefinitely long coordination strands into a two-dimensional (2D) layered structure. The electrochemical performance of Cd(DAB) was evaluated as an electrode material for supercapacitors. Owing to its high conductivity, it portrayed remarkable energy storage (pseudocapacitor) behavior; it exhibited a high specific capacitance of 1341.6 F g-1 and a long cycle life with 81% retention over 10,000 cycles at 20 A g-1. Additionally, an asymmetrical supercapacitor device was fabricated, which exhibited a specific capacitance of 428.5 F g-1 at a current density of 1 A g-1.

Coexistence of Redox‐Active Metal and Ligand Sites in Copper‐based 2D Conjugated Metal‐Organic Frameworks for Battery‐Supercapacitor hybrid systems

Two‐dimensional (2D) conjugated metal‐organic frameworks (c‐MOFs) are promising materials for supercapacitor (SC) electrodes due to their high electrochemically accessible surface area coupled with superior electrical conductivity compared to traditional MOFs. Here, porous and non‐porous HHB‐Cu (HHB=hexahydroxybenzene), derived through surfactant‐assisted synthesis, are studied as representative 2D c‐MOF models, showing different reversible redox reactions with Na+ and Li+ in aqueous and organic electrolytes, respectively. We deployed these redox activities to design negative electrodes for hybrid SCs (HSCs), combining the battery‐like property of HHB‐Cu as negative electrode and the high capacitance and robust cyclic stability of activated carbon (AC) as positive electrode. In organic electrolyte, porous HHB‐Cu‐based HSC achieves a maximum cell specific capacity (Cs) of 22.1 mAhg‐1 at 0.1 Ag‐1, specific energy (Es) of 15.55 Whkg‐1 at specific power (Ps) of 70.49 Wkg‐1, and 77% cyclic stability after 3000 gravimetric charge‐discharge (GCD) cycles at 1 Ag‐1 (calculated on the mass of both electrode materials). In the aqueous electrolyte, porous HHB‐Cu‐based HSC displays a Cs of 13.9 mAhg‐1 at 0.1 Ag‐1, Es of 6.13 Whkg‐1 at 44.05 Wkg‐1, and 72.3% Cs retention after 3000 GCD cycles. The non‐porous sample shows lower Es performance but better rate capability compared to the porous one.

Facile synthesis of hierarchically porous carbon monolith without templating agent for various applications in energy and catalysis

Monolithic carbon with hierarchically porous structure has a promising prospect for a wide range of applications in the fields of energy, environment, catalysis, etc. Due to the reliance on the utilization of templating agents, conventional preparation approaches often suffer from time-consuming preparation, complex post-processing, and uneconomical cost. Herein, we develop a novel strategy to match the sol-gel transition with the phase separation process for the direct preparation of hierarchically porous carbon monolith (HPCM) without templating agent. Resorcinol and resol are employed as carbon sources to adjust the polymerization for the formation of bi-continuous microstructure. Well-defined hierarchical pores and large specific surface area for fast mass diffusion enable the HPCM to be a prospective kind of electrode material in supercapacitor with an outstanding specific capacitance over 350 F g−1 (1.0 A g−1). After facile sulfonation, the modified HPCM can act as solid acid catalyst to realize a high-performance production of 5-hydroxymethylfurfural (5-HMF) in a 90 % yield with turnover frequency (TOF) value up to 155.9 h−1. Additionally, HPCM also exhibits an excellent Joule heating effect, which can be applied to the thermal management after compounding with phase change materials. The desirable integrated performance enables HPCM to be a valuable material suitable for various applications.

Boron-doped diamond decorated with metal-organic framework-derived compounds for high-voltage aqueous asymmetric supercapacitors

Conductive diamond has been recognized as a promising electrode material for supercapacitors due to its excellent stability and broad electrochemical potential window. To enhance the performance of diamond-based supercapacitors, this study focuses on two key strategies: incorporating redox-active species on the electrodes and/or in the electrolytes to increase the capacitance, and constructing asymmetric supercapacitors to expand the operating voltage range. In this context, pseudocapacitive Co3O4@boron doped diamond (BDD) and Bi–Bi2O3@BDD were synthesized using metal-organic framework (MOF) decorated BDD of Co-MOF@BDD and Bi-MOF@BDD as precursor materials, respectively. An aqueous asymmetric supercapacitor was then assembled using a pseudocapacitive electrode/redox electrolyte system of Co3O4@BDD | 3.0 M KOH+0.05 M K3Fe(CN)6/K4Fe(CN)6 as the positive compartment, and Bi–Bi2O3@BDD | 3.0 M KOH as the negative compartment. The resulting device demonstrated a wide operating voltage of 1.7 V, a maximal energy density of 10.0 Wh L−1 at a power density of 333.2 W L−1. The remarkable performance can be attributed to the Faradaic redox reactions involving [Fe(CN)6]3-/4-, Co3+/Co4+, Bi0/Bi2+/Bi3+ in the electrode materials and electrolytes. This work presents a novel way for fabricating aqueous supercapacitors with high voltage, high energy and power densities, offering significant potential for various energy storage applications.

Ultrasound-assisted fungal self-growth and heteroatom doping for the preparation of high-performance lignocellulose-based supercapacitor electrodes

Biomass materials are widely used as supercapacitor electrode materials due to their cost-effectiveness and eco-friendliness. In this work, ultrasound-assisted impregnation was employed for the thorough mixing of the liquid medium, and fungal treatment was conducted on the three main components of lignocellulose to prepare a fungi-modified heteroatom-doped lignocellulose-based carbon material (LCF-NP). The effects of heteroatom doping, the content of the three main components, and fungal modification on the electrochemical performance of lignocellulose-based carbon materials was investigated. The results revealed the synergistic effect of heteroatom doping and fungal treatment on the electrochemical performance. Compared with its counterpart free of fungal treatment, LCF-NP has a more reasonable pore structure and exhibits excellent electrochemical performance. LCF-NP porous carbon material has the highest specific surface area (792 m2/g), large pore volume (0.523 cm3/g), and ideal specific capacitance (1940 mF/cm2) under the conditions of 1.0 M Na2SO4 electrolyte and current density of 0.5 mA/cm2. After 10,000 cycles, there is almost no loss of capacitance. These results indicate that the joint utilization of heteroatom doping and fungal treatment has a promising application prospect in pore structure regulation and electrochemical performance improvement. This study provides a new strategy for the preparation of lignocellulose-based carbon electrode materials.

PEDOT: PSS Doped Activated Biochar as a Novel Composite Material for Photocatalytic and Efficient Energy Storage Application

Herein, we report the synthesis of activated biochar from green algae and the effect of its doping on the structural, photocatalytic, and energy storage properties of PEDOT-PSS. The morphology of pure and doped samples was investigated with Fourier Transform Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM), Brunauer–Emmett–Teller (BET) analysis, and thermogravimetric analysis (TGA). AFM results for PEDOT-PSS@6wt.% of BC indicate that the calculated average peak height, particle size, and roughness were 283 nm, 136 nm, and 71 nm, respectively. Adding biochar to PEDOT-PSS significantly improved the thermal stability of PEDOT-PSS up to 550 °C. The novel photocatalyst PEDOT-PSS@6wt.% BC improved photocatalytic performance by approximately 17% in Methylene Blue (MB) dye removal. The electrochemical performance in terms of supercapacitors for the synthesized samples was investigated using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), specific capacitance, stability, and electrochemical impedance spectra (EIS). PEDOT-PSS@6wt.% of BC as a novel electrode material in supercapacitors exhibits an initial specific capacitance of 1300 Fg−1. Moreover, the PEDOT-PSS@6wt.% of BC electrode shows excellent stability up to 1000 cycles of operation. The EIS studies suggest the presence of charge transfer resistance. Considering the economical biosynthesis and multifunctional features, the PEDOT-PSS@6wt.% of BC could potentially be used as a photocatalyst to remove organic dyes and supercapacitors in energy storage applications.

Enhancing the electrochemical performance of Ni-doped CuCo2O4 electrode material through 2D layered sheets

Abstract In the present study, the structural and electrochemical properties on Ni–CuCo2O4 (0 ≤ x ≤ 10 %) was studied for the use of active electrode materials in asymmetric supercapacitors prepared by a simple hydrothermal process. The synthesized material’s morphology shows that the nanosheets are assembled with an average diameter of about 50 nm, and the X-ray diffraction results show the spinel cubic structure with the space group of Fd-3mz (No. 227). CuCo2O4 electrodes exhibit a high specific capacitance for the electrodes because of the abundant redox reactions of Co2+/Co3+ and Co3+/Co4+, and Ni at the Co site has displayed exceptional charge-discharge and cyclic stability properties. The electrochemical studies show that the Ni doped CuCo2O4 electrode has the highest pseudocapacitive nature, with ultra-specific capacitances of 803 F g−1, 889 F g−1, 924 F g−1, and 1,086 F g−1 at 1 A g−1 respectively for pure, 2, 6, and 10 % Ni doped CuCo2O4 electrodes. Further, the excellent rate capability with 82 % capacitance retention and 92.3 % Coulombic efficiency were realized after 1,000 cycles. Moreover, the M-H study at room temperature showed paramagnetic behaviour. Additionally, the electrochemical and magnetic characteristics of the CuCo2O4 system is expected to improve as the doping quantity of Ni increased. This study may pave the way for enhanced properties of Ni doped CuCo2O4 for futuristic hybrid devices applications.