Three-electrode Configuration Research Articles

Two‐step electrodeposition of Hausmannite sulphur reduced graphene oxide and cobalt‐nickel layered double hydroxide heterostructure for high‐performance supercapacitor

Hausmannite/sulphur reduced graphene oxide (MO/RGO-S) and cobalt-nickel layered double hydroxide (CN) composite was synthesized through a two-step electrodeposition approach. This process began with galvanostatic electrodeposition of MO/RGO-Son a nickel foam, followed by cyclic voltammetry electrodeposition of CN. The inclusion of RGO-S increases the electrical conductivity of the active material (AM) and its wettability while Mn3O4 (MO) enhances the pseudocapacitive active sites which help to increase the specific capacity of CN. The materials' electrochemical evaluations were carried out via three- and two-electrode configurations using 2 M KOH electrolyte. An enhanced composite material (MO/RGO-S-50@CN) produced a phenomenal specific capacity of 582.1 mA h g−1 in a three-electrode configuration at 0.5 A g−1. The device (MO/RGO-S-50@CN//CCBW) consisting of MO/RGO-S-50@CN and activated carbon from cooked chicken bone waste (CCBW) as positive and negative electrodes, respectively delivered specific energy of 56.0 Wh kg−1 with a specific power of 515.0 W kg−1 at a specific current of 0.5 A g−1. The device produced capacity retention of 85.1% and coulombic efficiency of 99.7% at 10 000 galvanostatic charge-discharges cycles at 6 A g−1. Because of these excellent results, the fabricated materials demonstrated great potential for application as a high specific energy supercapacitor.

Comparative capacitive performance of MnSe encapsulated GO based nanocomposites for advanced electrochemical capacitor with rapid charge transport channels

In this work, series of manganese selenide (MnSe) and graphene oxide (GO) nanocomposites are prepared via a well-known hydrothermal route to investigate the impact of varying content of GO (5, 10, 15, and 20%) on the electrochemical properties of MnSe-GO composites. Phase and structural investigations of the as-prepared samples were carried out by using XRD. SEM analysis showed the successful formation of flakes-like morphology of MnSe wrapped on GO sheets, providing a conductive pathway for transmission of electrolyte ions. When tested thoroughly for supercapacitor electrodes in a three-electrode configuration, all electrodes revealed a pair of redox peaks originating from Mn2+/Mn3+ due to faradaic redox reactions owing to their pseudocapacitive behavior. Amongst all samples, the optimum electrochemical performance was achieved with the aid of 5% GO composite with MnSe, which exhibited a capacitance of 180 F g−1 with the lowest charge transfer resistance. For practical aspects, we designed and fabricated an asymmetric supercapacitor (ASC), which delivered a capacitance of 56.25 F g−1, an energy density of 31.25 Wh kg−1 at a power density of 6779.20 W kg−1. Remarkably, our fabricated ASC made of MnSe-GO//AC displayed an outstanding cycling performance with its initial capacitance retention of 86.3% when tested for 5000 successive charge-discharge cycles. Thus, based on the comparative results of MnSe based GO composites for energy storage, the performance of the MnSe nanomaterial can be further enhanced by using different carbon-based nanomaterials, a promosing approach to fabricate materials for future energy conversion and storage devices.

Fabrication of High-Performance Asymmetric Supercapacitor Consists of Nickel Oxide and Activated Carbon (NiO//AC)

Exploring faster, safer, and more efficient energy storage devices will motivate scientists to develop novel energy storage products with high performance. Herein, we report porous NiO nanoparticles have been prepared by a simple hydrothermal method with CTAB and laboratory tissue paper as a template followed by calcination at three different temperatures (300, 500, and 700 °C). The electrochemical characteristics of the prepared materials were examined in a three-electrode cell configuration using aqueous potassium hydroxide (2.0 M KOH) electrolyte. The NiO-300 electrode displayed the supreme capacitance of 568.7 F g−1 at 0.5 A g−1. The fascinating NiO morphology demonstrates a crucial part in offering simple ion transport, shortening electron, and ion passage channels and rich energetic spots for electrochemical reactions. Finally, the asymmetric supercapacitor (ASC), NiO//AC was constructed using positive and negative electrode materials of NiO-300 and activated carbon (AC), respectively. The assembled ASC displayed excellent supercapacitive performance with a high specific energy (52.4 Wh kg−1), specific power (800 W kg−1), and remarkable cycle life. After quick charging (25 s), such supercapacitors in the series will illuminate the light emitting diode for an extended time, suggesting improvements in energy storage, scalable integrated applications, and ensuring business efficacy. This work will lead to a new generation of high-performance ASCs to portable electronic displays and electric automobiles.

Hierarchical porous carbon derived from coal-based carbon foam for high-performance supercapacitors

Hierarchical porous carbon (HPC) from bituminous coal was designed and synthesized through pyrolysis foaming and KOH activation. The obtained HPC (NCF-KOH) were characterized by a high specific surface area (SBET) of 3472.41 m2/g, appropriate mesopores with Vmes/Vtotal of 57%, and a proper amount of surface oxygen content (10.03%). This NCF-KOH exhibited a high specific capacitance of 487 F/g at 1.0 A/g and a rate capability of 400 F/g at 50 A/g based on the three-electrode configuration. As an electrode for a symmetric capacitor, a specific capacitance of 299 F/g at 0.5 A/g was exhibited, and the specific capacitance retained 96% of the initial capacity at 5 A/g after 10,000 cycles. Furthermore, under the power density of 249.6 W/kg in 6 mol/L KOH, a high energy density of 10.34 Wh/kg was obtained. The excellent charge storage capability benefited from its interconnected hierarchical pore structure with high accessible surface area and the suitable amount of oxygen-containing functional groups. Thus, an effective strategy to synthesize HPC for high-performance supercapacitors serves as a promising way of converting coal into advanced carbon materials.

Rapid, sensitive and specific electrochemical detection of E. coli using graphitized mesoporous carbon modified electrodes

Escherichia coli (E. coli) is a highly pathogenic bacterium causing infections to the human body primarily from a variety of sources including food intake. As per the World Health Organization (WHO), the mortality and morbidity rate due to E. coli is significantly high, approximately 8%. Therefore, a real-time, rapid, user-friendly and interference-free E. coli detection system offers great clinical importance. In this work, a highly sensitive, specific, and simple method of electrochemical detection of E. coli has been demonstrated. The electrochemical system employs the conventional three-electrode configuration, wherein glassy carbon (GC), chemically modified with graphitized mesoporous carbon (GMC), has been employed as the working electrode. While using platinum and Ag/AgCl as counter and reference electrodes respectively, voltametric techniques were applied to obtain the interference mitigated response of E. coli detection. The GCE/GMC electrode showed excellent sensitivity and selective response towards E. coliin a linear detection range of 2.52 × 103 CFU/mL to 25.2 × 104 CFU/mL and 252CFU/mL to 2268CFU/mL respectively with a limit of detection (LOD) of 50.40CFU/mL. Further, the developed system was tested for interference with other bacteria and real samples, such as pond water, tap water, and deionized water. Appreciable recovery values and negligible interference were observed. The prepared electrode demonstrated promising results towards efficient, real-time, and rapid E. coli detection.

Self-Assembly of Hausmannite Mn3O4 Triangular Structures on Cocosin Protein Scaffolds for High Energy Density Symmetric Supercapacitor Application.

Recent advances in using biological scaffolds for nanoparticle synthesis have proven to be useful for preparing various nanostructures with uniform shape and size. Proteins are significant scaffolds for generating various nanostructures partly because of the presence of many functional groups to recognize different chemistries. In this endeavor, cocosin protein, an 11S allergen, is prepared from coconut fruit and employed as a potential scaffold for synthesizing Mn3O4 materials. The interaction between protein and manganese ions is studied in detail through isothermal calorimetric titration. At increased scaffold availability, the Mn3O4 material adopts the exact hexamer structure of the cocosin protein. The electrochemical supercapacitive properties of the cocosin-Mn3O4 material are found to have a high specific capacitance of 751.3 F g-1 at 1 A g-1 with cyclic stability (92% of capacitance retention after 5000 CV cycles) in a three-electrode configuration. The Mn3O4//Mn3O4 symmetric supercapacitor device delivers a specific capacitance of 203.8 F g-1 at 1 A g-1 and an outstanding energy and power density of 91.7 W h kg-1 and 899.5 W kg-1, respectively. These results show that cocosin-Mn3O4 could be considered a suitable electrode for energy storage applications. Moreover, the cocosin protein to be utilized as a novel scaffold in protein-nanomaterial chemistry could be useful for protein-assisted inorganic nanostructure synthesis in the future.

Two-Dimensional Metal–Organic Frameworks with Unique Oriented Layers for Oxygen Reduction Reaction: Tailoring the Activity through Exposed Crystal Facets

Two-Dimensional Metal–Organic Frameworks with Unique Oriented Layers for Oxygen Reduction Reaction: Tailoring the Activity through Exposed Crystal Facets

Improvement of the Supercapacitor Performance of Nickel Molybdenum Chalcogenides/Reduced Graphene Oxide Composites through Vanadium-Doping Induced Crystal Strain Relaxation and Band Gap Modification

Metal chalcogenide/reduced graphene oxide (RGO) composites have gained significant interest as promising electrode materials for supercapacitor application. Herein, the effect of different chalcogens (O, S, and Se) on nickel-based bimetallic composites along with the addition of a scanty amount of a heteroatom (V) is investigated. Different sizes and electronegativity of the chalcogens alter the morphology of the composites. However, V doping does not change the morphology but regulates the crystalline strain, band-gap energies, and charge transfer kinetics of the materials. All these factors are very important in controlling the performance of a supercapacitor device. Among all the doped and undoped composites, Se-based electrode materials exhibit the highest supercapacitor properties. In a three-electrode configuration, the V-doped Ni-Mo selenide/RGO (VNMSeR) composite electrode exhibits the highest specific capacitance of ∼610 C g–1 (1220 F g–1) at 2 A g–1 current density with a superior rate capability of ∼73.7%. An asymmetric supercapacitor device has been fabricated using VNMSeR as positive and thermally RGO as negative electrode. The device exhibits a maximum energy density of ∼60.5 Wh kg–1 at a power density of 1.47 kW kg–1 and shows ∼83.4% retention (50.5 Wh kg–1) in energy density when the power density increases by ∼8.25-fold (12.12 kW kg–1).

Sonication-supported synthesis of cobalt oxide assembled on an N-MWCNT composite for electrochemical supercapacitors via three-electrode configuration

The Co3O4@N-MWCNT composite was synthesized by a sonication-supported thermal reduction process for supercapacitor applications. The structural and morphological properties of the materials were characterized via Raman, XRD, XPS, SEM–EDX, and FE-TEM analysis. The composite electrode was constructed into a three-electrode configuration and examined by using CV, GCD and EIS analysis. The demonstrated electrochemical value of ~ 225 F/g at 0.5 A/g by the electrode made it appropriate for potential use in supercapacitor applications.

Biomass Straw-Derived Porous Carbon Synthesized for Supercapacitor by Ball Milling.

A large amount of biomass straw waste is generated every year in the world, which can cause serious environmental pollution and resource waste if disposed of improperly. At present, biomass-derived porous carbon materials prepared from biomass waste as a carbon source have garnered attention due to their renewability, huge reserves, low cost, and environmental benevolence. In this work, high-performance carbon materials were prepared via a one-step carbonization-activation method and ball milling, with waste tobacco straw as precursor and nano-ZnO as template and activator. The specific surface area and porous structure of biomass-derived carbon could be controlled by carbonization temperature, which is closely related to the electrochemical performances of the carbon material. It was found that, when the carbonization temperature was 800 °C, the biochar possesses maximum specific surface area (1293.2 m2·g−1) and exhibits high capacitance of 220.7 F·g−1, at 1 A·g−1 current density in a three-electrode configuration with 6 M KOH aqueous solution. The capacitance retention maintained about 94.83% at 5 A·g−1 after 3000 cycles. This work proves the porous biochar derived from tobacco straws has a great potential prospect in the field of supercapacitors.

Solvent modulated self‐assembled VS 2 layered microstructure for electrocatalytic water and urea decomposition

Urea oxidation reaction (UOR) assisted water-splitting is a promising approach for effective treatment of urea-rich waste-water at the anode and parallelly generate green-hydrogen (H2) energy at the cathode via hydrogen evolution reaction (HER). However, facile designing and fabricating robust and cheap electrodes derived from earth-abundant materials is a great challenge. This work reports the synthesis of vanadium sulfide (VS2) micro-flowered structure via solvent-assisted hydrothermal method using ethylene glycol as an additive in the aqueous-based reaction medium, which has imparted a significant effect on the morphology and the crystallinity of the VS2. In addition, in contrast to the VS2 electrode fabricated in a pure aqueous medium, the ethylene glycol mediated VS2 electrode upon coupling as a cathode and anode in an HER||UOR vs reversible hydrogen electrode (RHE)-based three-electrode configuration demonstrates a significantly reduced overall urea decomposition potential of 1.38 V at a current density of 10 mA cm−2 as compared to the conventional water-splitting of 1.75 V vs RHE. The obtained high-performance electrocatalytic activity on UOR and HER can be ascribed to the influence of ethylene glycol solvent, particularly on VS2 growth, morphology, and crystallinity, favoring the formation of abundant catalytic sites with facile electrolyte diffusion and electrolysis.

“One for two” strategy of fully integrated textile based supercapacitor powering an ultra-sensitive pressure sensor for wearable applications

Textile-based energy storage devices help realize the full potential of flexible electronics as they combine the functionality of wearable devices with the inherent high-power density and fast charging/discharging capability of supercapacitors. In this work, Nickel di-selenide (NiSe2) is grown on carbon cloth (CC) via a facile one-pot hydrothermal technique and is used for supercapacitor and pressure sensor to demonstrate a textile-based fully integrated system. In a three-electrode configuration, the NiSe2 electrode produces a half-cell specific capacitance of 980 Fg−1 at 1 Ag−1, indicating its high-rate capability. Further, the NiSe2 electrode is combined with activated carbon (AC) electrodes generated from biomass to construct an asymmetric supercapacitor device (ASC) with a 1.6 V of output voltage. The ASC device delivers maximum specific energy of 50 Whkg−1 at a current density of 1 Ag−1 and a maximum specific power of 900 Wkg−1 at 10 Ag−1. An ultra-sensitive pressure sensor is fabricated by sandwiching the NiSe2 grown carbon cloth between thin layers of PDMS, which exhibits a sensitivity of 0.91 kPa−1 in the wide dynamic pressure range of 1– 80 kPa−1. An exceptional mechanical stability is obtained for an unloading/loading of 1 kPa of pressure for 5000 cycles. Further, it is powered using the NiSe2/CC || AC/CC AFSC for steady and reliable detection of radial pulse pressure on the human wrist in real-time. This work paves a new path in exploring the potential of textiles when combined with nanomaterials to develop low-cost, self-powered healthcare systems for real-time monitoring of health parameters.

A Highly Efficient Graphene Gold Based Green Supercapacitor Coin Cell Device for Energy Storage

Inclination to exploit renewable energy and their potential storage by facile, cost-effective, and above all in a green way are exactly what the current alternative energy research is looking for. The high-performance supercapacitor devices made up with the electrode materials synthesized in a simple and ecofriendly way are in utmost demand and the ultimate goal for widespread commercialization. Keeping these points in view, one pot green synthesis of active electrode material rGO-Au composite is achieved which not only performs as a very good supercapacitor in three-electrode configuration but also demonstrates extremely well as a coin cell device, ready to use. Ascorbic acid, which is commonly found in citrus fruits, plays an important role to reduce graphene oxide into rGO and simultaneously gold salt into gold nanoparticles, resulting in rGO-Au composite. The maximum recorded specific capacitance by CV measurement is 303.02 Fg−1at a scan rate of 5 mVs−1. Hindrance in the commercialization is caused by the differences in the supercapacitor performances between three electrode configurations and finally the proposed device. Here the proposed coin cell device exhibits maximum areal and mass specific capacitance of 62.43 mFcm−2and 56.09 Fg−1, respectively, that is very high among all reported graphene based composite devices benefitted over with commercially viable high capacity retention up to 80% even after 10,000 cycles. The proposed device demonstrates high energy density (∼ ED= 7.79 Wh/Kg) comparable to batteries and an optimum power density (∼ PD= 2512.9 W/Kg) close to supercapacitor insinuating it is an effective green supercapacitor for commercialization.

Pyrazine-based organic electrode material for high-performance supercapacitor applications

Pseudocapacitors (PCs) exhibit high capacitance and high energy density, which renders incredible execution in energy storage gadgets. PCs bridge the gap between batteries and electrostatic double-layer capacitors (EDLCs). Herein, we designed novel electrode material i.e. naphtho[2,3-h]naphtho[2′,3′:5,6]quinoxalino[2,3-a]naphtho[2′,3′:5,6]quinoxaline [2,3-c]phenazine-5,12,17,22, 27,30-hexaone (Pyz-ANQ) composed of hexaketocyclohexane (HKCH) and 2,3-diaminoanthraquione (ANQ) subunits. The Pyz-ANQ electrode has been fabricated on a Toray carbon paper (CP) and used as a pseudocapacitor electrode which showed efficient pseudocapacitor performance in a three-electrode configuration. The specific capacitance (Csp) by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) analysis are 85.2 F g−1 at a scan rate of 5 mV s−1 and 43.1 F g−1 at current density 0.5 A g−1 in 1 M H2SO4, respectively. The PCs behavior is attributed to the reversible redox chemistry of Pyz-ANQ. Furthermore, we fused the material into a symmetric solid-state two-electrode supercapacitor (SSSC) device for practical demonstration of its potential in future energy storage applications and it shows the Csp value by two methods CV and GCD such as 52.5 F g−1 @ 5 mV s−1 and 36.6 F g−1 @ 0.5 A g−1, as well as it shows excellent cyclic performance in three-electrode and two-electrode system in the percentage of 78.8% and 75.9% for 2000 GCD cycles. Significantly, Pyz-ANQ/CP electrode has an energy density of 2.6 Wh kg−1 at 4.7 kW kg−1 of power density, respectively. In this way, by utilizing HKCH and ANQ in the redox system, Pyz-ANQ/CP results in pseudocapacitive energy storage, bringing a new dimension to improve the chemistry of organic supercapacitors.

Sustainable synthesis of apricot shell-derived hierarchical porous carbon for supercapacitors: A novel mild one-step synthesis process

Development for sustainability and renewable energy storage equipment with energy-efficient and environmentally-friendly characteristics being the overwhelming imperative problem that needs to be addressed. Here, apricot shells were used to prepare apricot shell-derived porous carbons (APCs) with hierarchical structures by employing a mild one-step method, viz. a CaCO3/K2C2O4 salt activator at 700 ℃. Pore structures for APCs can be regulated by the weight ratio of CaCO3 to K2C2O4. Significantly, the mild one-step preparation of APCs bypasses high temperatures (> 700 ℃), strong acids or alkalis, and supercritical drying or freeze-drying. The resultant optimal porous carbon APC-1 had a large specific surface area of 2348.96 m2/g and a low ratio (36.15%) of micropore volume (Vmicro) to total pore volume (Vtotal). Besides, APC-1 achieved a high specific capacitance of 300.41 F/g at 1 A/g in the three-electrode configuration and good capacitance retention of 85.88% at 10 A/g. Particularly, APC-1 displayed a high energy density of 29.54 Wh kg−1 upon 2800.83 W kg−1 in the two-electrode cell and excellent cycling stability of 91.56% capacitance retention after 10,000 cycles at 10 A/g. The present investigation gives a mild one-step approach to obtain biomass-derived porous carbons for high-performance supercapacitors.

Spinel-MgMn2O4 nanofibers: An attractive material for high performance aqueous symmetric supercapacitor

It is a known fact that morphology greatly influences the energy storage performance of a material. In this work, spinel magnesium manganese oxide (MgMn2O4) having nanofibric morphology has successfully been prepared for the first time using a versatile and cost-effective electrospinning technique. The morphology and the pore size are altered and optimized by varying the process parameters in the electrospinning process, and their corresponding effect on supercapacitive properties are also studied thoroughly. The aligned, mesoporous, and high aspect ratio of spinel-MgMn2O4 nanofiber exhibit the specific capacitance of ∼345 Fg−1 at 1 Ag−1 and 250 Fg−1 at 4 Ag−1 as well as demonstrate an outstanding rate capability and good capacity retention (∼90%) after 10,000 successive cycles at 4 Ag−1 in a three-electrode configuration. The improved energy storage performance of MgMn2O4 active material on graphite substrate is ascribed to its nanofibric morphology with interconnected particles having pores/voids in between, which impart a higher diffusion coefficient (D= 3.226 × 10−10 cm2s−1) and a small relaxation time constant (τ = 0.1 s). The quantitative capacitive contribution generating from EDLC and/or the surface pseudocapacitance reactions and the contribution from diffusion-controlled redox reactions to the total current have also been determined. The assembled symmetric all-solid-state supercapacitor (ASSSC) shows the high specific energy of ∼30 W h kg−1 at the specific power of ∼510 W kg−1 in the potential window of 0.0 V to 2 V with PVA-H2SO4 gel electrolyte. This performance is superior to that exhibited by many ASSSC reported recently. Two ASSSC devices connected in series can light up parallelly connected 55 red LEDs for more than 3 min, indicating practical applicability of our designed symmetric supercapacitor in electronics appliances. The outstanding electrochemical performance of the MgMn2O4 nanofiber reveals its potential to be a promising electrode material for supercapacitors.

Valorization of lignin: Application of lignin-derived activated carbon in capacitors and investigation of its textural properties and electrochemical performance

This work provides an idea for the efficient and harmless utilization of lignin and further evaluates the textural properties of lignin-derived activated carbon/specific capacitance relationship. The yield of apricot shell lignin (ASL) was 30.42%. H3PO4/KOH was used to assist the preparation of ASL-derived activated carbons (AACs) for capacitors. The AAC prepared at a ratio of H3PO4 weight to ASL weight of 3 (AAC-P-3) had a specific surface area of 1475.16 m2/g. Similarly, the AAC obtained at a ratio of KOH weight to ASL weight of 2 (AAC-K-2) owned a specific surface area of 2136.56 m2/g. At 0.50 A/g, the specific capacitance of AAC-P-3 and AAC-K-2 was 169.14 F/g and 236.00 F/g, respectively. The average value of the correlation coefficients (AR2) between specific surface area and specific capacitance was highest, i.e., 0.983, followed by the AR2 (0.978) between Vmicro/Vmeso and specific capacitance, the AR2 (0.975) between pore-wall thickness and specific capacitance. Consequently, when using a current density range of 0.50–10.00 A/g and a three-electrode configuration with a 6 M KOH electrolyte, the specific capacitance of AACs depends not only on the specific surface area but also on the Vmicro/Vmeso, pore-wall thickness, and Vmicro.

Hierarchical porous graphitized carbon xerogel for high performance supercapacitor

A facile and supercritical drying-free synthesis strategy is developed for rapid preparation of resorcinol-formaldehyde resin organic xerogel. An iron-based deep eutectic solvent is applied as both reaction medium and catalyst for the polymerization of resorcinol with formaldehyde. The coordination effect of Fe3+ greatly short the gelation time. Hierarchical porous carbon xerogel with both amorphous and graphitic regions is obtained via pyrolysis as prepared organic xerogel. By selectively etching the amorphous carbon domains of the product through a simple air etching treatment at 400 °C, a porous graphitized carbon xerogel is achieved. The carbon xerogel possesses a high specific surface area of 587 m2 g−1 and abundant surface oxygen functional groups. Consequently, the O–RFCX–700 sample delivers a specific capacitance of 209 F g−1 at a current density of 0.5 A g−1 and exhibits excellent rate performance (131 F g−1 at 10 A g−1) as well as cycling stability in a three-electrode configuration in 1 M KOH electrolyte. The present work paves a new way for rapid preparation of resorcinol-formaldehyde resin (xero)gel and extends their applications in energy storage devices.

Synthesis of CuCo2S4 nanoparticles assembled in micro-sized hollow spheres composed with polyaniline: An effective electrode material for supercapacitors

CuCo2S4 is a well-studied promising electrode material for energy storage devices. In this work we describe a method to further increase its electrochemical performance by forming hollow core–shell structures of CuCo2S4 and polyaniline. CuCo2S4 nanoparticles are synthesized in micro-sized hollow sphere assemblies through facile solvothermal method. They exhibit high capacitive behavior with specific capacitance of about 839F g−1 at current density of 1 A g−1 in three-electrode configuration. Oxidative polymerization of aniline on surface of these micro-sized hollow spheres leads to form an electrochemically improved nanocomposite and the specific capacitance is increased to about 1120F g−1 at current density of 1 A g−1. This superior capacitive performance can be attributed to the hollow core–shell structure of the obtained nanocomposite. The assembled symmetric supercapacitor device based on as-prepared CuCo2S4/PAni nanocomposite exhibits a wide working potential of 2 V in 1 M Na2SO4 which can reach a high energy density and power density of 44.16 Wh kg−1 and 1 kW kg−1, respectively.

Zeolitic imidazolate frameworks derived Co-Zn-nanoporous carbon-sulfide material for supercapacitors

To synthesize porous carbon-based electrodes for supercapacitors, a bimetallic strategy is used from zeolitic imidazolate frameworks (ZIFs), i.e., ZIF-67 and ZIF-8 are used for derived carbon material. The synthesized electrode comprises two metals, nitrogen and nanoporous carbon with sulfur, which have precisely controlled specific surface area, porosity, and graphitization degree. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge (GCD) methods are used to explore the electrochemical behavior of the prepared materials using three-electrode configurations in an electrolyte solution (2 M KOH). By combining the consequences of sulfur and bimetal, the prepared specimens performed exceptionally well. The modified final ZIF-derived bimetallic sulfide exhibited an enhanced specific capacitance value of 815 F/g at a scan rate of 2 mV/s. According to the findings, the modified composite has very little resistance to charge transfer, a fast frequency response time, and an improved specific capacitance value. The composite's coulombic efficiency remains at 83.9% after 5000 cycles. The final composite's outstanding performance is due to its nitrogen-doped nanoporous carbon nature/structure and bimetallic derived sulfide composition.