Electrode Material For Supercapacitor Applications Research Articles

Hydrothermal synthesis of GO/ZnO composites and their micromorphology and electrochemical performance

In this study, a graphene oxide/zinc oxide (GO/ZnO) composite was synthesized by the one-pot hydrothermal technique using various GO/ZnO ratio compositions. These were characterised by scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) and Raman spectroscopy. The findings reveal that the GO/ZnO composite has three different micromorphologies: ZnO-nanorods (ZnO-NRs) were embedded and agglomerated over the GO surface; ZnO-microrods (ZnO-uRs) adhered to and separated on the GO surface; and GO was coated by ZnO at 1:1, 1:2 and 1:8 ratios. In addition, the electrochemical performance of the synthesized GO/ZnO composites was investigated using cyclic voltammetry (CV). The results show that the embedded and agglomerate of ZnO-NRs over the GO surface have the best performance, indicated by a larger CV curve area and higher specific capacitance than the GO and other GO/ZnO composites. The results indicate that the incorporation and insertion of GO and ZnO NRs have an effective reversible nature and are promising electrode materials for supercapacitor applications.

Coalescing of lanthanum oxide and PPy @graphitic carbon nitride to achieve ultrahigh energy density electrode material for supercapacitors applications

Faster charging and discharging rate and long cycle life make supercapacitors compatible for energy storage devices. However, supercapacitors' poor energy density prevents them from replacing batteries. This study reports a facile method of synthesizing PPy/g-C3N4/La2O3 (LGP) nanocomposite electrodes via in-situ polymerization by varying the lanthanum oxide concentration. The electrochemical application of synthesized nanocomposites was performed in 1 M H2SO4 by cyclic voltammetry (CV), Galvanostatic Charge Discharge (GCD) and electrochemical impedance spectroscopy (EIS). It was observed that the addition of lanthanum oxide has a synergistic effect on already reported PPy/g-C3N4 composite resulting in a specific capacitance of 1763.56 F g−1 at 10 mV s−1 with ultrahigh energy density of 198.18 W h kg−1 and power density of 450.01 W kg−1 at a current density of 1 A g−1 for 0.4 LGP. From EIS studies, the solution resistance was 1.53 ohm and the charge transfer resistance was 0.50 ohm for PPy, while for 0.4 LGP it was 1.00 ohm and 0.23 ohm respectively. Additionally, the capacitance of 0.4 LGP composite increased to 131% after 10,000 cycles showing the enhanced cyclic stability of electrode material in 1 M H2SO4 electrolyte demonstrating its capability as an electrode material for future supercapacitors.

Microwave‐Induced Rapid Synthesis of MoS2@Cellulose Composites as an Efficient Electrode Material for Quasi‐Solid‐State Supercapacitor Application

Transition‐metal dichalcogenides (TMDs) are highly desired for energy‐storage devices due to their intrinsic layered structure, huge surface area, and the large number of active sites. However, the TMDs fail to reach their potential due to restacking of 2D layered structures that remains a major technological hurdle. Herein, MoS2 nanosheets and cellulose fiber binary composite (MoS2@Cellulose) prepared by the microwave‐assisted technique are demonstrated as an electrode material for supercapacitor application. The prepared material are tested in symmetric and asymmetric all solid‐state device assemblies. It is found that the quasi‐solid‐state symmetric and quasi‐solid‐state asymmetric supercapacitors exhibited remarkably higher specific capacitance of ≈294 and ≈177 F g−1 at a current density of 1 A g−1, respectively, than their counterpart. Furthermore, the symmetric and asymmetric devices deliver excellent energy densities of ≈40.84 and ≈42.67 Wh kg−1 while maintaining the power density of 400 and 791.81 W kg−1, respectively, and outstanding cyclic stability. The cellulose entanglement causes a reduction in the aggregation and restacking of MoS2, which may improve the electrochemical performance of the supercapacitor. Herein this research, a pathway is provided to create an efficient energy‐storage system using 2D materials with sustainable cellulose.

Design and fabrication of nickel vanadium sulfide directly grown on the basis of NiV-LDH nanosheets for high-performance supercapacitors

Herein, nickel-vanadium binary sulfide (NVS) was directly grown on the basis of nickel-vanadium layered double hydroxides (NiV-LDH) using the combination of hydrothermal method and gas-phase vulcanization method, forming a unique structure (NVS@NiV-LDH). The results suggest that the growth of NVS significantly increases the number of active sites and enhances the stability of the structure. The NVS@NiV-LDH electrode reaches a standout specific capacitance of 465.33 F g−1 at a high current density of 6 A g−1 and an excellent cycle stability of 90.69 % after 5000 charge-discharge cycles at 12 A g−1. Furthermore, an asymmetric supercapacitor (NVS@NiV-LDH//AC) was also assembled, achieving a high energy density of 133.98 Wh kg−1 at a high power density of 15,120 W kg−1 with a superior cycling stability (82.8 % of its initial specific capacitance after 5000 cycles at 12 A g−1). These results demonstrate an optimistic prospect of the NVS@NiV-LDH in electrode materials for supercapacitor applications.

N-Doped Carbon Dots and ZnO Conglomerated Electrodes for Optically Responsive Supercapacitor Applications

The over-dependence of human society on fossil fuels for energy is exhausting the level of such non-renewable energy sources. Alternative energy storage systems have gained more popularity recently to counter this issue. In this context, we report the fabrication of N-doped carbon dot (N-CD)-decorated ZnO-based electrodes for supercapacitor applications. Due to the light-responsive nature of the N-CDs and ZnO, the electrode was also responsive under the influence of UV light. After the experimental tests, it was found that the areal capacitance value of the supercapacitor increased upto ∼58.9% when illuminated compared to that under the dark conditions. Moreover, the device showed a maximum areal capacitance of 2.6 mF/cm2 after photocharging and galvanostatically discharging at a current density value of 1.6 μA/cm2, which is quite comparable with the previously reported data. The doping of N-CDs with ZnO showed a significant improvement in the areal capacitance value under both illuminated (∼58.64%) and dark conditions (∼22.08%) compared to the case of pristine ZnO, which justifies the purpose of attaching N-CDs with ZnO. Therefore, in brief, we have fabricated a photoresponsive electrode material for supercapacitor application by combining N-CDs and ZnO. An explicit electrochemical characterization of the electrode was also done to identify the contribution from diffusion-controlled capacitance and double layer capacitance, and it was observed that the diffusion-controlled capacitance gets reduced from 59.1 to 33.6% when the scan rate is increased from 2 to 75 mV/s. Moreover, a detailed study has also been done to understand the reaction mechanism. It was confirmed that the defects in the electrode material played a vital role in the intercalation of K+ ions.

Enhanced Electrochemical Performance of Supercapacitors via Two-Dimensional Indium Sulfide Heterostructure on Carbon Nanotubes

This study reports on the synthesis and characterization of a novel electrode material for supercapacitor applications based on a clustered heterostructure of indium sulfide (In2S3) and single-walled carbon nanotubes (SWCNTs). The In2S3-SWCNT (INSC) sample was prepared using the facile successive ionic layer adsorption and reaction (SILAR) method and demonstrated a higher specific capacitance (258 Fg−1 at 1 Ag−1) compared to the bare indium sulfide (In2S3) electrode. The enhanced electrochemical performance is attributed to the synergistic effect between the In2S3 and SWCNTs, which improves electron transportation, catalytic nature, and specific capacitance. Moreover, the cyclic stability of the INSC electrode was significantly improved, retaining 96.8% of the initial capacitance after 3000 cycles. The high voltage holding capacity and high cyclic efficiency of the fabricated INSC-based supercapacitor devices suggest their potential for next-generation energy storage devices. Additionally, the INSC electrode-based supercapacitor devices exhibit excellent flexibility and bendability, retaining similar performance even at a bending angle of 180°, making them suitable for flexible energy storage applications.

Synergistic effect in g-C3N4/CuO nanohybrid structures as efficient electrode material for supercapacitor applications

A facile thermal decomposition and hydrothermal techniques were used to fabricate g-C3N4/CuO nanohybrid electrode material. The pure g-C3N4, CuO and g-C3N4/CuO nanohybrid composites were confirmed by powder X-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM) and Fourier-transform infrared spectroscopy (FTIR). The g-C3N4/CuO electrode material exhibited a specific capacitance of 98F/g which is substantially higher than those using bare CuO (40F/g) and bare g-C3N4 electrodes (62F/g). Cycle-life data for over 2500 cycles reflect 19 % capacitance degradation for g-C3N4/CuO nanohybrid material. The energy density given by g-C3N4/CuO, CuO and g-C3N4 devices is 14.8 W h kg−1, 5 W h kg−1 and 6.3 W h kg−1 respectively. The enhanced electrochemical performance of the nanohybrid material is ascribed to synergistic effect and pseudo capacitive nature of the metal oxide nanoparticles incorporated in the g-C3N4 matrix.

Biomass-Derived N-Doped Activated Carbon from Eucalyptus Leaves as an Efficient Supercapacitor Electrode Material

Biomass-derived activated carbon is one of the promising electrode materials in supercapacitor applications. In this work bio-waste (oil extracted from eucalyptus leaves) was used as a carbon precursor to synthesize carbon material with ZnCl2 as a chemical activating agent and activated carbon was synthesized at various temperatures ranging from 400 to 800 °C. The activated carbon at 700 °C showed a surface area of 1027 m2 g−1 and a specific capacitance of 196 F g−1. In order to enhance the performance, activated carbon was doped with nitrogen-rich urea at a temperature of 700 °C. The obtained activated carbon and N-doped activated carbon was characterized by phase and crystal structural using (XRD and Raman), morphological using (SEM), and compositional analysis using (FTIR). The electrochemical measurements of carbon samples were evaluated using an electrochemical instrument and NAC-700 °C exhibited a specific capacitance of 258 F g−1 at a scan rate of 5 mV s−1 with a surface area of 1042 m2 g−1. Thus, surface area and functionalizing the groups with nitrogen showed better performance and it can be used as an electrode material for supercapacitor cell applications.

Mini-Review on Conducting Polymer–MoS2–Carbon Ternary Composite as a Hybrid Electrode Material for Supercapacitor Applications: Progress and Perspectives

Supercapacitors have drawn a lot of interest as a result of recent significant improvements in electronic devices to address the growing energy dilemma. In stoichiometric combinations of materials, the hybrid strategy of mixing an EDLC with a pseudocapacitive material can produce noticeable specific capacitance, energy, and power density with strong cycle stability. Research into developing more advanced hybrid materials finds a bright future based on the broad variety of applications in numerous power-related technologies. This brief overview summarizes recent advancements in research and technology pertaining to conducting polymer–MoS2–carbon ternary hybrid composite supercapacitors, their architectural design, and their performances.

Sol-Gel Derived Chromium Doped Vanadium Pentoxide Based Nanostructured Electrode Materials for Supercapacitor Applications

Through a simple sol-gel process, chromium doped vanadium pentoxide (V2-xCrxO5-δ, where x = 0, 0.05, 0.10, 0.15 and 0.20) nanomaterials were synthesized. The XRD data confirmed the occurrence of orthorhombic crystalline structure. FTIR spectra exhibited the presence of V = O and V-O-V along with carbon di oxide and moisture in the samples.The particle diameter was found to be 146-227nm. The SEM results exhibited a sheet like structure. From the electrochemical studies, it was found that V1.95Cr0.05O5-δ electrode has exhibited a specific capacitance of 232.15 Fg−1 at the scan rate of 10 mVS−1. It can be an electrode for supercpacitors.

Incorporation of α-MnO2 Nanoflowers into Zinc-Terephthalate Metal-Organic Frameworks for High-Performance Asymmetric Supercapacitors.

Herein, we report the synthesis of α-MnO2 nanoflower-incorporated zinc-terephthalate MOFs (MnO2@Zn-MOFs) via the conventional solution phase synthesis technique as an electrode material for supercapacitor applications. The material was characterized by powder-X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy techniques. The prepared electrode material exhibited a specific capacitance of 880.58 F g-1 at 5 A g-1, which is higher than the pure Zn-BDC (610.83 F g-1) and pure α-MnO2 (541.69 F g-1). Also, it showed a 94% capacitance retention of its initial value after 10,000 cycles at 10 A g-1. The improved performance is attributed to the increased number of reactive sites and improved redox activity due to MnO2 inclusion. Moreover, an asymmetric supercapacitor assembled using MnO2@Zn-MOF as the anode and carbon black as the cathode delivered a specific capacitance of 160 F g-1 at 3 A g-1 with a high energy density of 40.68 W h kg-1 at a power density of 20.24 kW kg-1 with an operating potential of 0-1.35 V. The ASC also exhibited a good cycle stability of 90% of its initial capacitance.

Structurally synergetic stabilization of polyvinylpyrrolidone and co-doping boosts robust interconnected Ni(OH)2 nanosheets for high-performance asymmetric supercapacitor

The occurrence of microcracks hinders the capacity performance and lifetime of electrode materials in energy storage systems. Herein, we report PVP-modified and Co doped Ni(OH)2 nanosheets with structurally robust interconnection fabricated on Ni foam by a facile hydrothermal process. Co-doping obviously makes the Ni(OH)2 nanosheets have fewer microcracks while no observable microcracks appear under PVP modification. The obtained P-CoNi-0.5 LDHs (layered double hydroxides) electrode presents the optimal specific capacitance of 2350 F g−1 (293.8 mA h g−1) at 1 A g−1 current density, which is about 3.12 times greater than that of CoNi-0 LDHs (pure Ni(OH)2). The excellent rate capability is obtained since the retained specific capacitance of 1706 F g−1 (213.3 mA h g−1) is achieved at 16 A g−1 current density. An asymmetric supercapacitor device is fabricated by using P-CoNi-0.5 LDHs and activated cow dung carbon (ACDC), as the positive and negative electrode materials respectively. It exhibits desirable energy and power densities up to 32.1 W h kg−1 at 800 W kg−1, and offers a fascinating electrochemical cyclic performance of 89.6 % capacitance retention after 4000 cycles. We suggest that the synergy of Co-doping and PVP modification makes it a promising electrode material for supercapacitor applications, and also provides a feasible strategy for the design and preparation of functional electrode materials.

N-doped reduced graphene oxide/MnO2/co-doped polyaniline ternary nanocomposites for electrochemical energy storage applications

The development and design of electrode materials with high electrochemical performance is of great importance for developing of supercapacitors, which are accepted as reliable power sources for portable and electric vehicles. Here, we have developed for the first time a ternary nanocomposite via a simple approach in which MnO2 and polyaniline (PANI) are simultaneously synthesized on nitrogen-doped reduced graphene oxide (N-rGO) surface using dodecylbenzenesulfonic acid (DBSA) and sulfuric acid (H2SO4) as co-dopants. The synergistic effect between combined N-rGO, MnO2, and co-doped PANI resulted in the N-rGO-MnO20.5-PANI6 nanocomposite exhibiting high capacitance (405.2 F/g) at a current density of 0.5 A/g and splendid rate capability (capacitance retention of 96.6 % at 5 A/g) with long cycle stability (86.1 % after 5000 cycles) in a symmetrical two-electrode configuration. The energy and power density of N-rGO-MnO2-PANI were determined to be 13.9 Wh/kg and 260.6 W/kg at a current density of 1 A/g, respectively. Consequently, the ternary nanocomposite with DBSA and H2SO4 co-doped PANI and MnO2 structures on N-rGO surface has appealing electrochemical performance and indicates great potential as an electrode material for supercapacitor applications.

Electrochemical pseudocapacitance of Co/Co2P/CoP as electrode material for supercapacitor application

It has become a consensus to study transition metal phosphides with abundant earth reserves and good electrochemical properties as electrode materials for supercapacitors. Among them, cobalt phosphide is particularly attractive because of its good electrical conductivity and theoretical specific capacity. Therefore, cobalt phosphide composites were prepared by hydrothermal reaction and phosphating reaction in this paper. Due to the synergistic effect of different components and the interfacial effect between the components, the ion transport and charge transfer kinetics of the prepared Co/Co2P/CoP electrode are both improved, which exhibits excellent electrochemical performance. At the current density of 1 A g−1, the prepared Co/Co2P/CoP electrode material has a specific capacitance of 193.3 mA h g−1, after 6000 cycles of charge and discharge at the current density of 2 A g−1, the specific capacitance maintains at 80 %. An asymmetric supercapacitor was assembled with the prepared material as the positive electrode and activated carbon as the negative electrode, which can provide an energy density of 37.87 W h kg−1 at a power density of 799.6 W kg−1. At the current density of 1 A g−1, the assembled supercapacitor can maintain 80 % of the initial specific capacitance after 5000 cycles. This provides ideas for future research on this type of energy storage materials.

Single-step synthesis of Mn3N2, MnxON and Mn3O4 nanoparticles by thermal plasma arc discharge technique and their comparative study as electrode material for supercapacitor application

In the present study, single-step synthesis of single-phase manganese nitride (Mn3N2), mixed phase manganese oxynitride (MnxON) and manganese oxide (Mn3O4) nanoparticles (NPs) was carried out using the thermal plasma arc discharge (TPAD) method. The experiments were carried out using nitrogen (N2), ammonia (NH3) and oxygen (O2) gas atmospheres at different plasma powers 2, 4 and 6 kW. The phase and elemental compositions of the prepared nanoparticles were examined using X-Ray Diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDX) analysis. All the synthesized powder samples have nearly spherical morphology, which are determined by using Field Emission Scanning Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM) analysis. The surface area of the prepared NPs was investigated using Brunauer-Emmett-Teller (BET) analysis, and the obtained results are 40.1, 19.4 and 11.8 m2g−1 for Mn3N2, MnxON and Mn3O4 NPs respectively. The Mn3N2 NPs showed superior storage performance with an outstanding specific capacitance of 508.4 F/g at 1 A/g with pseudocapacitive behavior compared to the mixed and oxide NPs 335.1 and 150 F/g respectively. The Mn3N2 electrode exhibited higher cycling stability with 84.2% capacitance retention after 5000 cycles at a current density of 5 A/g. These results demonstrated that the plasma-prepared single-phase Mn3N2, which is used as a potential electrode material for supercapacitors applications.

Impact of ZnO on structural and electrochemical properties of silver spinel ferrites for asymmetric supercapacitors

Supercapacitors are receiving great scientific attention as energy storage devices due to their rapid charge/discharge rates, high power densities, and high stability. Silver spinel ferrite (AgFe2O4) and its composites AgFe2O4@ZnO (5 & 10 %) have been synthesized by using the hydrothermal method. XRD showed that the prepared samples have a cubic spinel structure. The crystallite sizes of the samples vary from 20 to 27 nm. TEM results showed that all ferrite particles had a spherical morphology. In the UV–vis absorption spectrum, the estimated Eg was 4.9 eV for AgFe2O4 and Eg increased with higher ZnO concentration. The specific capacity for AgFe2O4@10 %ZnO is 585.4 C/g which is higher than 497 C/g for AgFe2O4@5%ZnO and 394.2 C/g for AgFe2O4. For making an asymmetric device AgFe2O4@10 %ZnO//AC, activated carbon was chosen as the negative electrode and AgFe2O4@10 %ZnO as the positive electrode. With this device, a specific capacity of 171.3 C/g was attained. AgFe2O4@10 %ZnO was found to have a power density of 720 W/kg and an energy density of 28 Wh/kg. This work indicates that a mixture of silver spinel ferrite composite (AgFe2O4@10 %ZnO) may be a more suitable electrode material for supercapacitor applications.

SnO2 quantum dots decorated BiOI nanoflowers as a high-performance electrode material for supercapacitor application

SnO2 quantum dots decorated BiOI nanoflowers as a high-performance electrode material for supercapacitor application

Ag@Fe3O4 nanoparticles decorated NrGO nanocomposite for supercapacitor application

There is still a great need for production and design of electrode materials with superior electrochemical properties for supercapacitor application. Nanocomposites containing graphene-based metal-metal oxide nanostructures are promising electrode materials because of their high conductivity, excellent surface properties, and effective charge storage with both EDLC and pseudocapacitance mechanisms. In this study, Ag@Fe3O4 core@shell nanoparticles decorated nitrogen doped reduced graphene oxide (NrGO) was obtained with a facile and simple method. On the surface of NrGO nanosheets, Ag nanoparticles were found to be coated with Fe3O4 nanoparticles with a particle size of 5–12 nm. The electrochemical measurements of NrGO-Ag@Fe3O4 nanocomposite were carried out in a two-electrode cell. The ternary nanocomposite exhibited 212.2 F/g specific capacitance at a current density of 1 A/g, as well as high cyclic stability, the NrGO-Ag@Fe3O4 nanocomposite retained 77 % of its specific capacitance after 10,000 cycles. The Ag@Fe3O4 decorated NrGO nanocomposite indicates great potential as an electrode material for supercapacitor applications.

NiCo2S4 combined 3D hierarchical porous carbon derived from lignin for high-performance supercapacitors

Metal sulfides with the nature of low electronegativity and high electrochemical activity are potentially considered effective electrode materials for supercapacitors. Meanwhile, hierarchical porous carbon (HPC) materials derived from eco-friendly enzymatic hydrolysis lignin are the ideal matrix for holding nanoparticles (NP) that allows the overall NP/HPC composite to achieve outstanding electrochemical performance. In this study, NiCo2S4 nanoparticles were in-situ synthesized on the inner surface of 3D HPC that derived from enzymatic hydrolysis lignin with a simple one-step solvothermal method, thus forming a high-performance composite electrode material for supercapacitor applications. As a result, the NiCo2S4/HPC composite yields an outstanding specific capacity of 1264.2 F g−1 at 1 A g−1 and also exhibits remarkable rate performance. Such remarkable property is attributed to the effective combination of NiCo2S4 plus HPC and their strong chemical bonds, which enable excellent electronic conductivity and abundant exposed electroactive sites. The asymmetric supercapacitor assembled by utilizing NiCo2S4/HPC and active carbon as the positive and negative electrodes, respectively, provide an excellent energy density of 32.05 Wh kg−1 at a power density of 193.9 W kg−1. This work puts forward a practical optimization strategy for metal sulfides used in electrochemical energy storage devices.

Facile one-pot synthesis of template-free porous sulfur-doped g-C3N4/Bi2S3 nanocomposite as efficient supercapacitor electrode materials

This work develops a facile one-step template-free approach to control the porous morphology of sulfur-doped g-C3N4/Bi2S3 (Sg-C3N4/Bi2S3) for a hybrid asymmetric supercapacitor (HASC). Herein, bismuth nitrate acted as a bismuth source and played an efficient role as a temporary template that generated pores within Sg-C3N4 sheets before transforming into Bi2S3 nanoparticles. This inventive porous construction can professionally boost the electrochemical behavior of the prepared material as electrode material for supercapacitor applications. These results point to the potential of the prepared composite (Bi2S3/Sg-C3N4-II) with a porous structure to be a promising electrode material for highly efficient supercapacitors. Promisingly, the designed device can deliver maximum Es of 6.2 Wh kg−1 at the corresponding Ps of 455 W kg−1 at the current density of 0.8 A g−1. The cycling stability performance of the assembled device retained 80 % of its initial capacity after 3000 cycles, signifying the applicable potential of Bi2S3/Sg-C3N4-II for supercapacitor applications.