Electrodes For Electrochemical Supercapacitors Research Articles

Enhancement of capacitance retention of ZnCo2S4@Metal organic framework composite electrodes by hydrothermal process

Metal organic framework-derived materials are promising electrodes for electrochemical supercapacitors due to their surface area, porosity, and excellent redox behaviors. In the present study the fabrication of ZnCo2S4 and ZnCo2S4@ZIF-67 composites synthesized by solid-state grinding and hydrothermal processing for supercapacitor utilization. Studies using XRD, XPS, FTIR, BET, FE-SEM, and HR-TEM are employed to validate the morphological, surface, and structural characteristics. Highly conductive ZnCo2S4 nanostructured materials are intercalated with MOF surfaces to enhance electron transport. The high number of active sites involved in the rapid electrochemical phase fluctuation using 1 M KOH electrolyte may be the cause of this. ZnCo2S4 and ZnCo2S4@ZIF-67 composites are used to create the working electrode, while a 1 M KOH electrolyte is used for the supercapacitor. By employing a three-electrode design, the created composite electrodes improve cyclic retention with specific capacitances of 245 and 447.14F/g at 1 A/g, respectively. Two electrode configurations are used to build ZnCo2S4@ZIF-67/1M KOH/SSC, which produced results of 151.42F/g at 1 A/g, 85.2 % capacitance retention at 7 A g−1 of 6000 cycles, and 18.93 Wh kg−1 energy density at 642.85 W kg−1 power density. Thus, the fabricated composite electrodes may find application in electrochemical symmetric supercapacitor via two electrode configuration systems.

Covalently linked 4-Aminopyridine on reduced graphene oxide for high performance electrochemical supercapacitor electrode material

The portability of electrical devices requires the demanding but essential task of improving supercapacitor energy density while preserving stability. Introducing an amine heterocyclic compound on a reduced graphene oxide (rGO) layer can enhance its capacity for energy storage. Here, we employed Catharanthus roseus flower extract as a green reducing agent to prepare rGO for the first time. A stable covalently linked 4-AP-rGO was produced through combining of 4-Aminopyridine on the rGO layer via nucleophilic substitution reaction process. The synthesized materials were systematically characterized by FT-IR, UV–visible, Raman, powder XRD, XPS, SEM, and TEM. Furthermore, the screen-printed carbon electrode (SPCE) was modified with 4AP-rGO (4AP-rGO/SPCE) to evaluate the electrochemical properties using CV, GCD, and EIS in 1 M H2SO4. The electrochemical performance of the 4AP-rGO/SPCE modified electrode was compared with unfunctionalized rGO. The pseudocapacitive efficacy of the 4AP-rGO was exceptional as evidenced by its high energy density (12.27 × 10−4 Wh kg−1), high power density (350.6 × 10−3 W kg−1), and high specific capacitance of (180.3 × 10−3 F g−1) at 1 A g-1. Over 10,000 cycles at 1 A g-1, it maintained 98.8 % capacitance, exhibiting exceptional cycling stability. The energy density of 4-AP-rGO is 2.1 times higher than that of rGO, indicating that it is a suitable candidate for energy storage applications.

Carbonized porous zeolitic imidazolate framework as promising electrode for electrochemical supercapacitors

In order to manufacture effective supercapacitors with improved electrochemical performance, it is imperative to investigate greater surface area electrode materials. This work describes the development of a cost-effective method for the carbonization of porous zeolitic imidazole framework (ZIF8) to utilize as electrode of electrochemical supercapacitors. The electrode materials were prepared by synthesizing highly porous ZIF8-P followed by pyrolysis at 500 °C (ZIF8-P-500). The pyrolysis of ZIF-8 significantly strengthened the porous behavior by maintaining their hexagonal particles and obtaining high surface to volume ratio. The measurements using constant current charge/discharge (GCD) and cyclic voltammetry (CV) were used to evaluate the electrochemical capacitance characteristics of the synthesized ZIF8-P based electrode. The supercapacitor assembly using the optimized ZIF8-P electrode exhibited a high specific capacitance of ∼423.9 Fg–1 with exceptional cycle stability by maintaining capacitance of ∼86.7 % from its initial capacitance after 5000 cycles. Thus, the results indicate that the ZIF8-P based supercapacitor offers a compelling path for creating porous carbon electrodes from MOFs using low cost pyrolysis for advancing supercapacitor technology.

Effect of air-annealing on the structure, surface morphology, and supercapacitive properties of the 2D-BiOCl nanosheets

Upright-standing nanosheets of bismuth oxychloride (BiOCl), synthesized via a facile chemical synthesis method and air-annealed from 50 to 600 ℃ temperatures (named BOC-50–600), are envisaged as electrochemical supercapacitor electrodes. These electrodes are initially screened for their surface morphology, elemental configuration, phase purity, and binding energy by various means. Due to changes in the surface morphology, phase, charge transfer resistance, and binding energy, the one annealed at 150 ℃ i.e., BOC-150 has offered targeted supercapacitive performance due to quasi-faradaic redox reactions in 6 M KOH electrolyte solution. The specific capacitance of the BOC-150 electrode, measured at 1.40–5.0 A/g current densities, varies from 264.6 to 95 F/g. The as-assembled BOC-150//BOC-150 symmetric supercapacitor device (SSD) demonstrates an efficient supercapacitive performance with a maximum 86.87 Wh/kg energy density and 3735 W/kg power density. Additionally, the as-designed SSD endows an admirable capacity retention of 81.6% for 5000 charge-discharge cycles, approving moderate chemical stability and considerable mechanical robustness for use in commercial electronic items.

Investigation of the effect of carbonization temperature of plant biomass on the electrochemical properties of carbon material

Porous carbon materials (PСM) with different pore distributions in size and size of the specific surface area up to 250 m2/g were obtained by changing the carbonization temperature of plant biomass, namely walnut shells. The electrodes of electrochemical supercapacitors are formed based on the obtained carbon materials. The electrochemical behavior of PCM in 33% aqueous KOH solution has been studied by cyclic voltammetry and galvanostatic discharge-discharge methods and the value of their specific capacitance. The physicochemical processes occurring at the carbon electrode/electrolyte interface have been investigated by the method of impedance spectroscopy.

Porous Mn2O3 nanorods-based electrode for high-performance electrochemical supercapacitor

In this research, we introduce an effective electrode material, i.e. porous manganese oxide (Mn2O3) nanorods (NRs) prepared by simple hydrothermal process, designed for use in electrochemical supercapacitors. XRD analysis unequivocally confirms that the Mn2O3 NRs possess a pure cubic crystalline structure with an Ia3 space group, indicating the high degree of crystallinity and phase purity. Morphological examinations confirmed that the Mn2O3 NRs display a distinct rod-like structure, featuring an average size of around 30 nm, underscoring their nanostructured characteristics. The electrochemical performance of the synthesized Mn2O3 NRs as electrodes for supercapacitors was thoroughly examined, resulting in an impressive specific capacitance of 483 F/g at a scan rate of 10 mV/s. Electrochemical impedance spectroscopy (EIS) analysis was carried out to assess the effective series resistance (ESR), revealing a minimal resistance value of 3.2 Ω, highlighting excellent charge transfer kinetics. Mn2O3 NRs electrode displayed exceptional capacitance retention even after undergoing 500 charge–discharge cycles at a high current density of 5 A/g, indicating their remarkable chemical stability as an electrode material. This study introduces a promising and scalable approach for the development of high-performance supercapacitors, with Mn2O3 NRs as a critical component, and offers valuable insights into the design and engineering of advanced energy storage devices.

Covalently incorporated heterocyclic benzotriazole-reduced graphene oxide as a High-Performance electrochemical supercapacitor electrode

Enhancing supercapacitor energy density while maintaining stability is challenging but crucial for portable electronic devices. Functionalizing graphene can enhance its energy storage properties. Here, we used Senna auriculata flower extract as a green reducing agent for the first-time synthesis of reduced graphene oxide (rGO). Covalently linked BTA-rGO was synthesized by incorporating benzotriazole (BTA) on the rGO surface. BTA-rGO's electrochemical properties were studied via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge (GCD) in 1 M H2SO4 electrolyte. BTA-rGO exhibited a high-specific capacitance of 393 × 10−3 F g−1 at 1 A/g, excellent pseudocapacitive performance, a high energy density of 12.5 × 10−4 Wh kg−1, and a high-power density of 251 × 10−3 W kg−1. It retained 96.2 % capacitance over 15,000 cycles at 1 A/g, demonstrating remarkable cycling stability and 1.2 times higher energy density than rGO, underscoring its suitability for energy storage applications.

Correction: Vertically aligned boron-doped diamond nanostructures as highly efficient electrodes for electrochemical supercapacitors

Correction for ‘Vertically aligned boron-doped diamond nanostructures as highly efficient electrodes for electrochemical supercapacitors' by Shradha Suman et al., J. Mater. Chem. A, 2024, https://doi.org/10.1039/D3TA07728D.

Vertically aligned boron-doped diamond nanostructures as highly efficient electrodes for electrochemical supercapacitors

Nanostructured boron-doped diamond (BDD) offers a sizeable ion-accessible area, high mechanical robustness, and high electrical conductivity, which could be a suitable electrode for high-performance electrochemical (EC) supercapacitors. Herein, two morphological...

Sputtered vanadium carbon nitride (VCN) thin films: a potential electrode for supercapacitors

The preparation of efficient thin film-based electrode materials is a vital prerequisite for practical energy storage devices. Herein, we have prepared unique vanadium carbon nitride (VCN) thin films on FTO substrates by pulsed DC magnetron sputtering technique for competent supercapacitor electrodes. XRD analysis confirmed the crystalline nature of VCN thin films. SEM and AFM revealed a smooth morphology with an average grain size of 30 nm. Raman spectra showed two broad peaks around 1346 and 1589 cm−1, belonging to the D-band and G-band of VCN. The surface electronic states of VCN were investigated by XPS analysis, which confirmed the formation of pure VCN films without any impurities. The electrochemical performance of the thin film electrode was evaluated using cyclic voltammetry (CV), Galvanostatic charge–discharge (GCD), and Electrochemical impedance analysis (EIS). The electrochemical results showed the VCN thin films exhibited super capacitive behaviours. The maximum specific capacitance (Cs) value of 78.2 F g−1 was obtained from GCD studies. A variation in charge transfer resistance is detected from the EIS study, which arises due to the partial oxidation of the active nitride component. The VCN electrode showed good cycling stability, retaining 87% of its capacitance at a current density of 5 A g−1 even after 2000 cycles. The sputtered VCN films have been demonstrated as potential thin film electrodes for electrochemical supercapacitors for practical energy storage devices.

Covalently anchored benzimidazole-reduced graphene oxide as efficient electrochemical supercapacitor electrode material

Covalently anchored benzimidazole-reduced graphene oxide as efficient electrochemical supercapacitor electrode material

Co-sputtered V2O5–TiN composite on Ag-network current collector for high-performance flexible transparent thin-film supercapacitors

Next-generation wearables require extremely capable electrochemical energy-storage devices that exhibit improved performance with high flexibility and transparency. Herein, we present a highly flexible and transparent electrochemical thin-film supercapacitor electrode fabricated by co-sputtering V2O5 and TiN on an Ag-network-based current collector. The electrodes' physical properties, optical properties, and structural morphologies are studied using X-ray diffraction, UV–visible spectroscopy, and scanning electron microscopy, respectively. A symmetric device is fabricated using V2O5 and TiN on an Ag network, and the TiN sputter power is varied to optimize the performance. The device performance of the co-sputtered electrodes at various composition ratios is studied. The optimized V2O5–TiN (200−40)/Ag electrode device with pseudocapacitive behavior delivers an excellent areal specific capacitance of 98.66 mF cm–2 at a current density of 4 mA cm–2 with a charge retention of 90.12 % after 6000 cycles. The V2O5–TiN (200−40)/Ag electrode device outperforms other reported electrodes, with an energy density and power density of 30.83 μWh cm–2 and 2999.67 μW cm–2, respectively, and excellent mechanical stability.

Sol-gel method preparation and high-rate energy storage of high-entropy ceramic (FeCoCrMnNi)C porous powder

Among the existing electrochemical capacitive energy storage electrode materials, the (TiNbTaZrHf)C, (VCrNbMoZr)2N, (CoCrFeMnNi)3O4, (FeCoCrMnMg)3O4 and (FeCoCrMnCuZn)3O4 all have excellent capacitive performance, but the energy density is limited due to the narrow potential window. In order to solve the problem of low energy density of electrochemical supercapacitor, a kind of high-entropy carbides (HEMCs) with broad potential window is designed from generalized analysis of electrochemical window of active elements. This high-entropy carbide contains five active elements of Fe, Co, Cr, Mn and Ni. The prepared HEMC-3 has abundant pores and a specific surface area of 417.8 m2 g−1. The large specific surface area makes the HEMCs have high-rate energy storage performance. Electrochemical tests show that the HEMC-3 presents a potential window of [-1.0, 0.6] versus Hg/HgO, and can obtain a specific capacitance of 169.7 F g−1 at a current density of 0.5 A g−1. Due to the designed wide potential window of the prepared HEMCs, the energy density has been greatly improved, which shows a new strategy for developing of electrochemical supercapacitor electrode materials.

Facile one-pot synthesis of porous NiCoP@reduced graphene oxide composite as active electrode material for high energy density asymmetric supercapacitor

The superior properties of nanomaterials with a special structure can provide prospects for highly efficient supercapacitors for energy storage applications. Herein, a facile one step hydrothermal process is developed for the synthesis of NiCoP@reduced graphene oxide (NiCoP@RGO) composite as electrode for electrochemical supercapacitors. Furthermore, we report the improvements in the materials technology, demonstrating the NiCoP@RGO nanocomposite electrode with an excellent specific capacitance of 1541–1301 Fg−1 at 1–20 Ag−1, high capacitance retention of 92%, and long cycle life of 5000 cycles. The practical application is showcased in an asymmetric supercapacitor with a high active-material loading. Besides, an asymmetric supercapacitor assembled using the NiCoP@RGO as cathode active material and the activated carbon (AC) as anode active material exhibited a high capacitance of 146 Fg−1 at 1 A g−1 and a high energy density of 49.8 Whkg−1 at a power density of 1245.8 Wkg−1 at an operating voltage of 0–1.6 V, suggesting its promising application as a high-performance electrical energy storage device.

A study on the supercapacitive behaviour of SNrGO/PEDOT:PSS composite as an electrode for electrochemical supercapacitors

A study on the supercapacitive behaviour of SNrGO/PEDOT:PSS composite as an electrode for electrochemical supercapacitors

Three-dimensional FeNiP decorated graphene sponge: A novel flexible electrode for high-performance asymmetric supercapacitor

Here, a three-dimensional (3D) flexible material was prepared based on FeNiP decorated graphene sponge (GrS) by a two-step method. Free-standing 3D GrS was fabricated through a simple foaming-drying method, then FeNiP was electrodeposited onto flexible GrS material to achieve a flexible FeNiP/GrS sponge electrode for high-performance electrochemical supercapacitors. This composite material exhibited a high specific capacitance of 2292 F/g and 90% of the specific capacitance was retained after 10,000 charge/discharge cycles at a current density of 1 A/g. An asymmetric supercapacitor (FeNiP/GrS//GrS) was fabricated and this flexible circuit delivered a maximum power density of 6545 W/kg and a high energy density of 330 Wh/kg. This outstanding electrochemical performance could be attributed to the high charge conductivity of FeNiP and porous graphene sponge which provides good structure stability, large reaction surface area, and high electron transfer.

Heterogeneous nucleation and growth of interlaced CuO nanosheets on porous nickel foams as binder-free electrode material

The monoclinic CuO has a natural tendency to grow into sheet-like structures from alkaline solutions without the need for any specialized reaction conditions or structural directing agents. We demonstrate this growth habit of CuO by heterogeneously nucleating it onto Ni foam substrate from just the ammonical solutions of Cu salts. The growth kinetics were found to be fast and, dense, interlaced thin films with an average sheet width of 20 nm can be grown by simply controlling the degree of supersaturation of the solution. Strongly adhered films with thicknesses up-to 5 μm were deposited from three different Cu salt solutions. Due to faster growth kinetics, growth time has little effect on both the film and nanosheet thickness. Detailed structural and compositional characterizations of the CuO nanosheets were made using FESEM, HRTEM, SAED, XRD and, XPS. The utility of the grown CuO nanosheets is demonstrated as a ready to use electrode for electrochemical supercapacitors. Specific capacitance in excess of 498 F/g was calculated from the Galvanostatic charge–discharge measurements collected at a current density of 0.5 A/g.

A coactive performance of Ag2WO4 nanorods wreathed on the N-doped carbon nanofibers as electrode for electrochemical supercapacitors

The thriving energy demand of the gradually increasing population and modernised life style requires development in energy storage devices for usage in commercial electronic devices. In this particular work, we have explored electrochemical performances of bimetallic oxide Ag2WO4 nanorods and tuned its performance by decorating it on the nitrogen doped carbon nanofiber (N-CNF). The Ag2WO4 nanorods are synthesised by a facile route of co-precipitation method followed by ultrasonication with N-CNF. The synthesised Ag2WO4 nanorods was found electrochemically active and the incorporation of N-CNF end up boosting its electrochemical performances. The obtained nanocomposites were characterised by various advanced techniques. The amount of N-CNF was determined by characterisation via the potentiostatic and galvanostatic cycle measurements and electrochemical impedance spectroscopy (EIS). The electrochemically active Ag2WO4 with 20 wt. % of N-CNF (Ag2WO4/N-CNFb) exhibited 2.2-fold higher charge storage capacity than pristine Ag2WO4. The Ag2WO4/N-CNFb exhibited specific capacitance as high as 330 F g-1 at a constant applied current density of 1 A g-1 in 1 M KOH. The improved capacity may be due to conductive pathways provided by N-CNF. The Ag2WO4 got well decorated over the N-CNF facilitating the active sites interaction with electrolyte. The symmetric device fabricated with Ag2WO4/N-CNFb electrodes exhibited excellent energy density of 10 W h kg-1 at 6000 W kg-1 at 5 A g-1. The Ag2WO4/N-CNFb electrode long-term stability has been minutely observed; the high Coulombic efficiency of 90% and high rate of capacity retention 98% even after 3000 cycles. Owing to these excellent electrochemical properties, the research work can potentially widen the opportunity to explore other profound bimetallic oxides and its nanocomposites with conductive carbon-based matrix for energy storage applications.

Effect of pyrolysis temperature on carbon materials derived from reed residue waste biomass for use in supercapacitor electrodes

Activated carbon (AC) obtained by the pyrolysis of reed residue waste has been investigated for its potential application as a high-performance electrode material in supercapacitors. Four different pyrolysis temperatures (500, 600, 700, and 800 °C) were implemented, and the optimum pyrolysis temperature was determined on the basis of the physicochemical properties and electrochemical measurements of the AC materials. AC obtained at a relatively low pyrolysis temperature of 600 °C (denoted as C/600 °C) presented a Hemistepta lyrata (bunge flower)-like porous nanostructure with a high specific surface area of 2074.72 m2 g−1 and a large pore volume of 0.930 cm3 g−1. SEM and Raman spectroscopy have been used to inspect the surface morphology and assess the degree of graphitization of the AC materials. Electrochemical performances have been assessed by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. Sample C/600 °C displayed a relatively large capacitance of 228 F g−1 at a current density of 1 A g−1 in 6 m KOH as the electrolyte, and it retained very good cyclic stability with a capacitance retention of 98.1% after 8000 cycles at a current density of 5.0 A g−1. The results imply that C/600 °C derived from reed residue waste constitutes a promising electrochemical supercapacitor electrode material.

Facile preparation of PANI/MoOx nanowires decorated MXene film electrodes for electrochemical supercapacitors

Two-dimensional (2D) carbides and nitrides of transition metals (MXene) show great potential in supercapacitor electrodes because of high metallic conductivity, surface hydrophilicity and excellent electrochemical properties. However, the restacking and agglomeration of 2D MXene severely limit its application in energy storage devices. Herein, the PANI/MoOx nanowires decorated MXene (PMM) film electrodes are rationally designed and successfully achieved via a vacuum-assisted filtration method. The introduction of PANI/MoOx nanowires not only mitigates the restacking of MXene matrix, but also provides more transport channels and storage space for ions. The PMM composite film with 20 wt.% PANI/MoOx nanowires (labeled as PMM-20) used as supercapacitor electrodes can possess a high specific capacitance of 450 F/g at 5 mV/s and a high capacitance retention of about 91.5% after 10,000 cycles at 20 A/g. Furthermore, the symmetric supercapacitors based on the PMM-20 composite film electrodes show an energy density of 19.53 Wh/kg at a power density of 1610.11 W/kg. Thus, the PMM film electrodes with excellent electrochemical properties provide new insights into the rational design of supercapacitor electrodes, exhibiting a great potential use in the application of energy storage devices.