Supercapacitor Electrode Research Articles

Hydrothermally Synthesized Cobalt‐Doped NiO Nanoflakes: Enhanced Electrochemical Performance for High‐Performance Supercapacitors

This study examines cobalt‐doped nickel oxide (Co‐NiO) nanomaterials synthesized through a hydrothermal method, focusing on their potential as high‐performance electrodes for supercapacitors. By varying cobalt dopant concentrations (X = 0, 0.01, 0.05, 0.1), we aimed to enhance the electrochemical properties through strategic Co‐doping. The CoxNi1‐xO nanomaterials were characterized using several techniques, including X‐ray diffraction (XRD), UV‐visible spectroscopy, field emission scanning electron microscopy (FESEM), X‐ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), chronopotentiometry (CP), and electrochemical impedance spectroscopy (EIS). The analysis showed that Co‐doping preserved the NiO phase structure while significantly altering the morphology and electrochemical characteristics. The sample with (X = 0.1) achieved a specific capacitance of 880 F/g at a current density of 1 A/g, significantly outperforming the undoped NiO, which had a capacitance of 335 F/g. Additionally, the Co‐NiO demonstrated 83.3% capacitance retention after 1000 cycles at a current density of 10 A/g. These findings highlight the potential of Co‐NiO as an effective electrode material for supercapacitors.

Preparation and Characterization of Supercapacitor Cells Using Modified CNTs and Bimetallic MOFs

The synthesis of CoZn-MOF was accomplished via a simple hydrothermal method. The characterization of the synthesized materials was performed using X-ray diffraction (XRD), providing a thorough understanding of their structure and content. Subsequently, carbon nanotubes (CNTs) underwent three different pretreatment procedures prior to their application as an anode in a supercapacitor (SC) arrangement, with CoZn-MOF functioning as the cathode. The use of CNTs as electrode material led to an inherent improvement in conductivity and an intrinsic increase in the specific capacitance of the supercapacitor. Galvanostatic charge–discharge measurements of the three cells with different electrodes proved that the supercapacitor based on the CNT (acetic acid)//CoZn-MOF exhibited a capacity of 0.2285 F/g, a moderate energy density of 0.1944 Whkg−1 at a power density of 26.48 Wkg−1 as compared to the other two supercapacitors (CNT (nitric acid)//CoZn-MOF and CNT (unprocessed)//CoZn-MOF). This study utilized the advantages of carbon nanotubes in supercapacitor electrodes and examined the impact of CNT pretreatment.

Highly dispersed CoWO4 nanoparticles anchored on CNT as electrode for hybrid supercapacitor by microwave-assisted hydrothermal synthesis

Highly dispersed CoWO4 nanoparticles anchored on CNT as electrode for hybrid supercapacitor by microwave-assisted hydrothermal synthesis

Synthesis of Cu doped Ba(OH)2 thin film by SILAR method for supercapacitor electrode application

Abstract An economically suitable successive ionic layer adsorption and reaction (SILAR) method has been used to deposit 0.25, 0.50 and 0.75 wt% copper doped barium hydroxide on stainless steel (SS) substrate. X-ray diffraction analysis shows the orthorhombic crystal structure of Cu doped Ba(OH)2 electrode. FTIR analysis reveals the chemical bonds present in the sample. The energy-dispersive x-ray spectroscopy (EDAX) and x-ray photo electron spectroscopy (XPS) measurements have been performed to confirm Cu doping into Ba(OH)2. The electrochemical properties of Cu doped Ba(OH)2 electrode have been analysed by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) techniques. The 0.50 wt% Cu doped barium hydroxide electrode exhibits the highest specific capacitance (Csp) of 356.12 F g−1 (59.55 mF cm−2) at 1 mV s−1 scan rate in 1 M Na2SO4 electrolyte solution. This electrode also shows ~ 85% capacitance retention up to 8000 cycles. A symmetric device has also been fabricated by using two electrodes. This device shows energy and power densities of 1.13 Wh Kg-1 and 279.7 W Kg-1 respectively. This cyclic retention and capacitive behaviour of Cu-doped Ba(OH)2 shows its utility as an energy storage material in the near future.

MnOOH nanorods decorated with CeO2 nanoparticles as advanced electrode for high-performance supercapacitor

The development of novel composite electrode materials is essential to fabricating supercapacitors with high specific capacitance and good stability. In this study, MnOOH nanorods adorned with CeO2 (CeMn composites) have been satisfactorily synthesized through in-situ growth of tiny CeO2 nanoparticles using hydrothermal treatment. SEM images revealed that the granular CeO2 particles are adhered to the surfaces of nanorod-shaped MnOOH. XRD analysis confirmed the CeMn composites maintain the crystal structure of MnOOH and CeO2 with high purity. The EDS elemental mapping images demonstrated that Mn, O, and Ce elements are homogenously dispersion distributed in the CeMn composites. The supercapacitive performance of the MnOOH and CeMn composites pasted onto the Ni foam was evaluated determined through electrochemical measurements. The Ce0.05Mn1 (Ce/Mn molar ratio of 0.05/1) as a supercapacitor electrode exhibited an excellent specific capacitance of 857.62 F/g at 1 A/g, which is higher than the values for the MnOOH. Moreover, the prepared Ce0.05Mn1 still could retain good cycling stability over 3000 charge/discharge cycles. This study presents a feasible route to develop high-performing supercapacitor electrode materials.

Investigation of the Electrochemical Performance of Manganese Based Layered Double Hydroxides for Energy Storage Applications

Supercapacitors are a rapidly evolving technology with immense potential for applications requiring fast energy exchange and high-power delivery. They hold promise for revolutionizing areas like electric vehicles, renewable energy integration, and portable electronics. Layered double hydroxides (LDHs) offer several advantages as supercapacitor electrodes. Unlike batteries that rely on bulk reactions, LDHs store energy through surface interactions, enabling supercapacitors made with LDHs to charge and discharge very quickly. In this work, NiMn, CuMn and CoMn LDHs, which are promising materials for supercapacitor electrodes, are synthesized using an easy hydrothermal method. NiMn LDHs were made with a constant 3:1 Ni:Mn ratio during a range of synthesis timeframes, including 3, 5, 6, and 8 hrs. After electrochemical analysis, NiMn LDH-6 was discovered to have a maximum specific capacitance of 90 F g-1 at 10 mV s-1 as well as exceptional energy and power densities of 6.2 Wh kg-1 and 165.6 W kg-1, respectively. It is noteworthy that CoMn LDH, which was synthesized in the same conditions for six hours, performed even better, with specific capacitance of 104.93 F g-1, energy density of 7.39 Wh kg-1 with a power density of 132.48 W kg-1. An LED set up was activated to demonstrate the practical energy storage uses of CoMn LDH-6 with three supercapacitor cells attached in series. Using this set up, seven red LEDs lighted for 3 mins and twelve green LEDs for 2 mins. The present work underscores the vital function of synthesis time in enhancing the performance of NiMn LDH and showcases the capability of CoMn LDH as an expanded alternative for supercapacitor applications.

Hydrothermal synthesis of rGO-decorated NiMn2O4 nanoneedles for high-performance positive electrode in asymmetric supercapacitors

Pseudocapacitive electrode materials inherently have low electron conductivity, which prevents an energetic material from being fully utilised. We were able to produce effective hierarchical NiMn2O4/rGO composites, which provide an appealing solution to this issue. The composites were synthesised using a one-step hydrothermal approach. Due to the high electrical conductivity of reduced graphene oxide (rGO), the needles on plate like morphology of NiMn2O4, and the strong hold of dynamic materials to the current collector, the resulting hybrid electrodes exhibit a specific capacitance of 1628 Fg−1 at a current density of 1 Ag−1. They also demonstrate excellent rate performance and remarkable cycling stability, with a capacitance retention of 97.4 % after 10,000 cycles. In addition, the NiMn2O4/rGO//AC asymmetric supercapacitor (ASC) exhibits a peak energy density of 45Whkg−1 when operated at a power density of 3240 Wkg−1. The ASC device has an impressive ultralong cycling life, with a capacitance retention rate of 89.1 % after undergoing 10,000 charge/discharge cycles. The NiMn2O4/rGO composites provide a scalable production method and demonstrate outstanding electrochemical performance. This presents an opportunity to create innovative hybrid electrodes for enhanced supercapacitors.

Fabrication and Electrochemical Insights into Advanced rGO-modified Ternary Cu-doped NiFe2O4/TiO₂ Electrodes for High Performance Supercapacitors

In this study, we employed a comparative approach by evaluating the composites CuFe2O4-rGO-TiO2 (CFRT4), NiFe2O4-rGO-TiO2 (NFRT5) and Cu0.5Ni0.5Fe2O4-rGO-TiO2 (CNFRT6) against single compounds, CuFe2O4 (CF1), NiFe2O4 (NF2) and Cu0.5Ni0.5Fe2O4 (CNF3). The electrodes were fabricated using drop-cast technique and investigated using XRD, FESEM, FTIR, XPS, VSM and BET. CNFRT6 showed highest specific surface area of 14.57 m2/g. Using symmetric two electrode system with 3M H2SO4 electrolyte, in CV analysis, specific capacitance of CNFRT6 was determined to be 48.4 F/g at 10 mV/s. GCD analysis revealed that CNFRT6 attained highest specific capacitance value of 213.18 F/g at the current density of 0.25 A/g. The CNFRT6 yielded energy density (Ed) of 18.95 Wh/Kg at current density 0.25 A/g. Further, it achieved power density (Pd) of 1200 W/Kg at 3 A/g. Obtained results suggest that Cu0.5Ni0.5Fe2O4-rGO-TiO2 composite exhibited enhanced electrochemical properties and thus, it can be employed to fabricate electrodes for application in supercapacitors.

Waste wood tar based porous carbon electrodes for supercapacitors with excellent performances through condensation cross-linking modification

Wood tar is an unavoidable by-product during a slow-pyrolysis process of biomass, which is usually discarded as a waste and results in environment pollution. Recently, wood tar has been used as a starting material for carbon electrodes because of its thermoplasticity and high carbon content. However, wood tar is mainly composed of various light phenolic molecules, which usually leads to a low carbonization yield after carbonization and an inferior electrochemical performance after activation. In this work, in order to improve the carbonization rate and electrochemical performance of these materials, wood tar was first condensed and crosslinked with formaldehyde and urea via a condensation reaction to produce condensed macromolecular resins, which were then carbonized at 550°C and activated with KOH at 800°C to prepare high-performance nitrogen-doped carbon electrodes for supercapacitors. The samples possess high carbonization yield, large specific surface area (3515.1 m2g-1) and moderate nitrogen content (1.11%). The high-performance carbon electrodes fabricated by this method achieves a high capacitance of 437.8Fg-1 (6M KOH electrolyte) at 1A/g-1. The assembled supercapacitor has an energy density of 13.41Whkg-1 at a power density of 124.93Wkg-1. And the capacitance retention was essentially 100% after 10000 cycles at 5Ag-1. The study presents an innovative strategy for the production of porous carbon for supercapacitors using wood tar and improves carbonization yield via condensation cross-linking modification.

Direct solid–vapor approach to 2D FeCoNiP@N-graphene-CNTs as robust electrode material for high-performance supercapacitors

Carbon supported bi(tri)-metallic phosphides are well known high-active electrode nanomaterials as it poses multiple redox sites, excellent electrochemical reversibility, and stability. In spite of that the synthesis of metal phosphides are limited as it involves multiple steps, harsh preparation conditions and often pose poor metal-support interactions. Herein, a simple and direct one-step solvent-free solid–vapor method was developed for the fabrication of bi(tri)-metallic phosphides supported N-graphene/N-CNTs 2D-nanosandwidch, first report to the best of our knowledge. Unique surface morphology, high surface area, good thermal stability and strong metal-support interaction, were confirmed for the as prepared electrocatalysts (FeNiP/NCNTs, FeCoP/NCNTs and FeNiCoP/NCNTs). In three electrode system, the FeNiCoP/NCNTs showed highest specific capacitance of 1479F/g at 1 A/g in 3 M KOH and excellent cycling stability, with capacitance retention of 90.8 % over 5000 cycles. Interestingly in the two-electrode system, the FeNiCoP/NCNTs demonstrated impressive capacitance of 245F/g at 1 A/g, power density of 10567 W/kg and energy density of 66.7 Wh/kg, with excellent retention of 91.5 % over 5000 cycles. The direct one-step preparation and high electrochemical performance inclusively promote the present FeNiCoP/NCNTs (with low metal loading of less than 10 wt%) as a promising supercapacitor electrode nanomaterial for energy storage applications.

Ternary metal oxide carbon composite as high-performance electrode material for supercapacitor applications

Recently, ternary metal oxides carbon composites recognized as metal organic frameworks (MOFs) have gained striking attention for supercapacitor electrode material due to high surface area, porosity, chemical stability, tunable properties, redox activity, and eco-friendly material. ZIF-67 is a novel MOF possessing these characteristics. Therefore, the present work reports the development of ternary iron-nickel–cobalt ZIF-67 composites (FeNiCo ZIF-67) using co-precipitation method with the variation in molar concentration of iron oxide, nickel oxide, and cobalt oxide. Physico-chemical characterizations of developed materials were investigated through X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray (EDX), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) to confirm the successful formation of composites and structure, morphology. Then, the electrodes were fabricated for all three synthesized composites and electrochemical analyses such as cyclic voltammetry (CV), galvanic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) were performed. The results revealed the porous polyhedral structure of FeNiCo ZIF-67 with different compositions consisting of interconnected nanoparticles played an important role in increasing the charge storage capacity of the material. Among the composites, FeNiCo ZIF-67 (1:2:1) electrode material achieved the highest specific capacitance of 532.7 F/g at a current density of 1 A/g. FeNiCo ZIF-67 (1:2:1) exhibited maximum electrochemical active surface area 89.12. Electrochemical impedance spectroscopy (EIS) demonstrated the minimal resistance of 7.8 Ω by FeNiCo ZIF-67 (1:2:1) composite electrode compared to the other two electrode materials. Cyclic stability study revealed the capacitance retention of 91 % after 10,000 continuous charge discharge cycles at a current density of 10 A/g. Electrode material demonstrated an outstanding electrochemical performance, and this work could provide a simple strategy to fabricate FeNiCo ZIF-67 nanostructured electrode materials for supercapacitors.

Enhanced super capacitance performance of V₂O₅·nH₂O/g-C₃N₄ nanocomposites: Synthesis, characterizations, and electrochemical properties

The primary problem addressed in this study is to enhance the performance of supercapacitor electrode materials by developing a cost-effective, and efficient synthesis method for nanocomposites with high capacitance. Hence, in this study, we report the synthesis of V2O5·nH2O/g-C3N4 nanocomposites using a cost-effective hydrothermal method, resulting in four distinct samples: pristine V2O5·nH2O nanoribbons (VO) and three composites with varying amounts of g-C3N4 (10, 20, and 30 mg), labelled as VCN1, VCN2, and VCN3. Structural, morphological, optical, and electrochemical characterizations were conducted to assess their potential as supercapacitor electrode materials. Electrochemical analysis, including cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD), confirmed pseudocapacitance behavior in all samples. VCN1, containing 10 mg of g-C3N4 in V2O5·nH2O matrix, exhibited the highest specific capacitance of 230 F/g at a scan rate of 10 mV/s in a 3M KOH electrolyte. This enhancement in capacitance is attributed to the added g-C3N4, which increases active sites, as confirmed by Electrochemically Active Surface Area (EASA) measurements. Additionally, electrochemical impedance spectroscopy (EIS) supported VCN1's superior performance, identifying it as a promising, cost-effective electrode material for super capacitor applications.

Hydrangea-like NiMn Layered Double Hydroxide Grown on Biomass-Derived Porous Carbon as a High-Performance Supercapacitor Electrode

Hydrangea-like NiMn Layered Double Hydroxide Grown on Biomass-Derived Porous Carbon as a High-Performance Supercapacitor Electrode

Using tanned leather waste to derive biochars for supercapacitor electrodes in various electrolytes

Using tanned leather waste to derive biochars for supercapacitor electrodes in various electrolytes

Fabrication of binder-free MXene/reduced graphene oxide/W18O49 film electrode for flexible supercapacitors

MXene nanosheets tend to aggregate during operation, significantly impeding their utility. Yet, the defect can be validly solved by incorporating intercalation substances. Herein, binder-free MXene/reduced graphene oxide/W18O49 (MXene/rGO/W18O49) film is fabricated as supercapacitor electrode. W18O49 and rGO can foster the formation of interlayer structure with MXene nanosheets. This enlarging of interlamellar spacing facilitates establishing multidirectional ion transport routes and exposing more active sites. MXene/rGO/W18O49 manifests 581.2 F g−1 specific capacitance at 1 A g−1. Moreover, the assembled asymmetric supercapacitor (ASC), comprising of MXene/rGO/W18O49 and activated carbon (AC) as positive and negative electrodes, exhibits 1.6 V voltage window, along with 43.2 Wh kg−1 energy density at 799.8 W kg−1 power density. Notably, it retains 87.1 % capacitance after 10,000 cycles at 3 A g−1. Optimization strategy for MXene/rGO/W18O49 film as electrode not only illustrates the viability of MXene advancement, but also offers significant technical backing for its utilization in the next generation of flexible devices.

Designing micro-3D hierarchical HZCNF@ZS-LDH@MX as advanced electrodes for flexible supercapacitors

The design of electrode materials is the core for enhancing the practicality of supercapacitors. Herein, we report an electrode material with a micro-3D structure, in which the template-shaped ZnS nanorods are fixed on the hollow carbon nanofibers. Subsequently, ZnCo-LDH nanosheets grow on the surface of ZnS nanorods directionally and form a 3D structure. Finally, an MXene layer is coated on the material surface by electrostatic spraying. Experimental analysis shows that due to the construction of a stable polymetallic compound array and a conductive network, the HZCNF@ZS-LDH@MX electrode can maintain rapid charge transfer, thereby significantly improving the kinetics of ion/electron reactions. Taking these advantage, HZCNF@ZS-LDH@MX has a high specific capacitance of 830 F g−1, a specific surface area of 740 m2 g−1, and good cycling stability over 20,000 cycles. In addition, the assembled flexible device reaches an energy density of 65.1 Wh kg−1, which is sufficient to power an LED board. This study proposes an effective strategy for enhancing the ion and charge transport within the hierarchical structure. By making full use of the advantages of two-dimensional materials and designing micro-3D structures, it has opened up new approaches for the development and utilization of supercapacitor electrodes. In addition, according to the special nature of the material, the ability of electromagnetic wave absorbing is further tested. The results showed that the maximum reflection loss is −60 dB, and there is a potential application possibility of dual functions of energy storage and wave absorption.

Optimizing sponge-like activated carbon from Manihot esculenta tubers for high-performance supercapacitors

Activated carbon plays a crucial role in enhancing supercapacitor performance by optimizing parameters such as surface area, pore structure, and morphology. This study investigates activated carbon derived from Manihot esculenta tubers, which offers a promising, sponge-like porous morphology suitable for supercapacitor electrodes. Activated carbon derived from Manihot esculenta tubers was synthesized utilizing chemical activation with varying concentrations of potassium hydroxide (KOH) as the activator 0 M (C-S0), 1 M (AC-S1M), 2 M (AC-S2M), and 4 M (AC-S4M). The AC-S4M sample variant achieved the highest surface area (471.645 m2g−1) and total volume (0.253 cm3g−1). Electrochemical characterization using symmetric coin cell supercapacitors demonstrated excellent specific capacitance of 146.570 Fg−1 at 0.1 Ag−1 in a 6 M KOH aqueous electrolyte. Notably, the highest energy density of 15.525 Whkg−1 at a power density of 174.660 Wkg−1 was achieved. These results underscore the potential of Manihot esculenta tubers-derived activated carbon as a sustainable, high-performance electrode material, advancing environmentally friendly energy storage technologies, which remain interesting for further studies.

Cellulose Nanofiber-Supported Electrochemical Percolation of Capacitive Nanomaterials with 0D, 1D, and 2D Structures.

Cellulose nanofiber (CNF) represents a promising support material to strengthen the mechanical property of free-standing supercapacitor electrodes comprised of conducting nanomaterials. Although efforts have been focused on improving the performance of the CNF-supported electrode, the percolation of capacitive nanomaterials within the insulating CNF matrix, and its correlation with the nanomaterial's dimensionality are still underexplored. In this work, membrane supercapacitor electrodes are fabricated by incorporating CNF with 0D, 1D, and 2D capacitive nanocarbons respectively to study the impact of their dimensionality. It is found that the percolation pathway of the nanocarbons is dependent on their dimensionality. By introducing a new definition termed as electrochemical percolation threshold, the threshold weight percentages to realize effective electrochemical percolation are determined to be 60.0, 14.3, and 66.7% for 0D, 1D, and 2D nanocarbons, respectively. Increasing the weight percentage beyond the threshold typically results in improved electrochemical percolation but reduced mechanical strength, and both trends are dependent on the nanocarbon's dimensionality. The results provide guidance to design efficient and robust CNF-supported supercapacitor electrodes by controlling the dimensionality and density of the active material. The insights regarding the electrochemical percolation threshold can be applied to other energy-storage nanomaterials to advance the development of insulator-supported supercapacitors.

A comparative study on exploring sputtered titanium nitride thin films for high-performance supercapacitors

Magnetron sputtered titanium nitride (TiN) thin films possessed desirable electrochemical and physical characteristics making them attractive candidates for supercapacitor electrodes. Herein, the electrochemical performance of TiN films prepared via direct and reactive sputtering methods is investigated as electrodes for supercapacitor. Microstructural analysis revealed distinct morphologies, topographies, and crystal structures for each film type, with reactively sputtered TiN (RS) displaying a pyramidal structure indicative of (111) orientation, whereas directly sputtered TiN (DS) exhibited a granular structure. Electrochemical techniques like cyclic voltammetry, galvanic charge-discharge, and electrochemical impedance spectroscopy clarified the charge storage mechanisms and capacitance behavior. RS exhibited a quasi-rectangular CV profile with pseudo-capacitive behavior with low charge transfer resistance and peak specific capacitance of 90 mF cm−2 along with superior cyclic stability and ion conductivity. Supercapattery configuration was setup to validate those findings using reactive sputtered thin films. It demonstrated enhanced capacitance retention and low charge transfer resistance, highlighting their potential for practical applications in energy storage systems.

Fabrication of NiCo2O4 deposited self-doped TiO2 nanotubes as binder-free supercapacitor electrode

Fabrication of NiCo2O4 deposited self-doped TiO2 nanotubes as binder-free supercapacitor electrode