Electrode For Asymmetric Supercapacitors Research Articles

Controllable synthesis of nano-spherical and spinel structure hausmannite for asymmetric supercapacitor electrode application with long-term cyclic stability and its photocatalytic activity

Spinel structured materials have been developed as a potential candidate for energy storage applications due to their tunable electronic and structural properties. The nano spherical Mn3O4 spinel structure was synthesized using a polyvinylpyrrolidone (PVP) assisted hydrothermal approach. Owing to the smaller nano spherical architecture, and the impressive surface properties, the Mn3O4 shows outstanding surface characteristics to provide more reaction centers and shorten the ion transport path. Here, the addition of PVP reduces the battery-like diffusive behavior of the Mn3O4 electrode, induces capacitive behavior, and improves both high energy density and power density in a single material and cycling stability. In three-electrode configurations, Mn3O4 exhibits specific capacitance (628.7 Fg−1 at 1 Ag−1) and long-term cyclic stability (94% at 100 mV s−1 for 5000 cycles) in 1 M Na2SO4 electrolyte. The asymmetric device offers a high energy density of 35.41 Wh kg−1 with a power density of 850 W kg−1 and cyclic stability of 96.5% after 10000 charge/discharge cycles at 12 Ag−1. Density functional theory (DFT) is explained by electronic structural features and further investigated the photocatalytic activity of Mn3O4 samples on the model dye of Methylene Blue degradation.

Perylene diimide incorporated activated carbon as a composite electrode for asymmetric supercapacitor

Organic molecules-based supercapacitors have piqued interest as an efficient energy storage component. In this study, an organic composite based asymmetric supercapacitor has been developed using optimized amount of perylene diimide (PDI) in combination with activated carbon. The composite sample with 1 wt% PDI showed remarkable electrochemical performance, with a specific capacitance/(specific capacity) of 617 F/g/(171.3 mAh/g) at 0.5 A/g, higher than that of the individual components. Further, the assembled asymmetric device PPAC/PDI-1//PPAC delivered a high energy density of 62.3 Wh/kg at a power density of 455 W/kg, while retaining 91.4 % of its initial specific capacitance after 10,000 charge-discharge cycles. This study provides an avenue for the utilization of organic molecules for super-capacitor application owing to its polarity and conjugation with carbon.

Retraction Note: Fabrication of hexagonal shaped CuCo2S4 nanodiscs/graphene composites as advanced electrodes for asymmetric supercapacitors and dye sensitized solar cells (DSSCs)

Retraction Note: Fabrication of hexagonal shaped CuCo2S4 nanodiscs/graphene composites as advanced electrodes for asymmetric supercapacitors and dye sensitized solar cells (DSSCs)

Three-dimensional carbon-based endogenous-exogenous MoO2 composites as high-performance negative electrode in asymmetric supercapacitors and efficient electrocatalyst for oxygen evolution reaction

It is not an easy way to design composite electrodes with a high concentration of the constituent. This study cleverly exploited the phase transformation of molybdenum oxide to synthesize three-dimensional carbon-based endogenous-exogenous MoO2 composites (EEC) by a two-step process. MC-15 exhibited the most outstanding electrochemical performance among EEC, with a specific capacitance up to 411.1 F g−1 in Na2SO4, due to the design of MoO2, which could be highly loaded with three-dimensional carbon. In addition, the electrode capacitance remains up to 94.1% after 5000 cycles, attributed to the synergy effect of three-dimensional carbon and molybdenum dioxide by providing an abundance of active sites for MoO2 and overcoming its stacking. In this way, the electrochemical properties of the EEC electrode are not compromised by the volume expansion during the electrochemical process. The energy density of the asymmetric supercapacitor using this material as the negative electrode and MnO2@CC is 14 W h kg−1 at a power density of 802 W kg−1, showing a significant increase in energy density over the asymmetric supercapacitor with a conventional negative electrode (activated carbon, energy density of 3.36 W h kg−1 and power density of 700 W kg−1). Its specific capacitance remained 84.9% after 2500 cycles. In addition, an overpotential of only 348 mV was required to drive oxygen evolution in alkaline electrolytes with a Tafel slope as low as 88.7 mV dec−1; the 20 h stability test retains almost 100%. The results show that the design optimization of the negative electrode material provides a simple and effective strategy to increase the energy density of supercapacitors, and EEC electrode materials are a great candidate to be utilized in supercapacitors with excellent performance as well as electrolytic water.

Titanium carbide@Poly (3,4-propylenedioxythiophene) composite as electrode for asymmetric flexible supercapacitors

In this paper, the composite of Ti3C2Tx and poly (3,4-propylenedioxythiophene) (PProDOT) is prepared via a simple in-situ chemical oxidative polymerization. The optimum ratio of Ti3C2Tx@PProDOT composite with an outstanding capacitance of 462 C g−1 (462 F g−1) at 1 A g−1 is obtained by adjusting the mass ratio of Ti3C2Tx and ProDOT. The asymmetric flexible supercapacitor with Ti3C2Tx@PProDOT (1:10)//AC exhibits the gravimetric capacity of 238 C g−1 at 1 A g−1, and the retention of initial capacity remains at 79.6% after 10,000 cycles. Meanwhile, the asymmetrical supercapacitor displays an energy density of 48.6 Wh kg−1 at a power density of 729.6 W kg−1. The improvement of these properties stems from that the PProDOT effectively inhibits the stacking of Ti3C2Tx sheets, which is advantageous to shortening the transport path of ions and promoting electron transport as well as the rapid redox reactions. Therefore, these characteristics enhance the electrochemical performance of composites.

Redox-active conjugated microporous anthraquinonylamine-based polymer network grafted with activated graphene toward high-performance flexible asymmetric supercapacitor electrodes

Conjugated microporous polymer (CMP) networks with multi-dimensional structure and excellent physicochemical stability with tunable porosity are receiving increased interest. Herein, we report a composite of anthraquinonylamine-based CMP network and activated graphene (CMAP@AG hybrid) via facile Buchwald-Hartwig coupling. The hybrid composites are made via chemical grafting of CMAP onto AG samples prepared with varied activation treatment times. The grafting of CMAP with AG provides a good hybrid morphology, and its structural properties are tuned by controlling the activation step of AG since both porosity and flake size of the AG sample depend on the etching conditions. The optimized CMAP@AG hybrid exhibits a large surface area of 498 m2 g−1 and low sheet resistance of 278 Ω sq−1, and it can be directly used as an electrode material for supercapacitors. The CMAP@AG hybrid electrode shows a three-electrode specific capacitance of 751 F g−1 at a current density of 1 A g−1 with a good rate capability. A quasi-solid-state CMAP@AG//AG asymmetric supercapacitor (ASC) displays a high energy density of 76.6 Wh kg−1, a power density of 27,634 W kg−1, and good cycle stability with mechanical flexibility. These investigations offer insight into a rational design of CMP-based activated graphene composite for energy storage devices.

WS2-embedded MXene/GO hybrid nanosheets as electrodes for asymmetric supercapacitors and hydrogen evolution reactions

MXene-related materials are auspicious electrodes for energy storage/conversion application due to their various features, including large surface area, high metallic conductivity, and fast redox activity; however, their surface aggregation and oxidation have significantly restricted their application in various industries. This study demonstrated the fabrication of porous WS2 nanosheets-interconnected MXene/GO (WS2@MXene/GO) nanocomposites using a simple hydrothermal reaction for electrochemical supercapacitors and water splitting reactions. The assembled WS2@MXene/GO nanocomposites electrode produced a superior specific capacitance of ∼ 1111F g−1 at 2 A/g applied current. Further, the asymmetric device constructed using the nanocomposite delivered the high specific energy of ∼ 114 Wh kg−1 and asymmetric capacitance of 320F g−1 along with an exceptional cycling stability. The WS2@MXene/GO nanocomposites electrocatalyst exhibited low overpotentials of 42 and 45 mV and small Tafel slopes values of 43 and 58 mV.dec−1 for hydrogen evolution reaction in acidic and alkaline medium, respectively. In addition, density functional theory (DFT) approximations validated the observed experimental results using density of states, Gibbs free energy for H-adsorption, and quantum capacitance calculations.

Ni–Mo–O@Ni–P nanowires as binder-free electrodes for aqueous asymmetric supercapacitors with high specific capacity and excellent stability

Ni–Mo–O@Ni–P nanowires as binder-free electrodes for aqueous asymmetric supercapacitors with high specific capacity and excellent stability

Immoderate nanoarchitectures of bimetallic MOF derived Ni–Fe–O/NPC on porous carbon nanofibers as freestanding electrode for asymmetric supercapacitors

The logical design and engineering of bimetallic oxide nanomaterials with porous carbon materials have had a significant impact on the development of high-performance electrode materials for energy storage devices in recent years. The vertical and uniform building of porous multimetal nanomaterials on the surface of nanoscale carbon fibers is difficult but not impossible. We present a self-templated metal-organic framework (MOF)-based strategy for the synthesis and assembly of bimetallic oxides/nanoporous carbon nanostructures (Ni–Fe–O/NPC) on porous carbon nanofibers (PCNFs). The vertical alignment of Ni–Fe–O/NPC at PCNFs favors a fast redox reaction by shortening the ion/electrode diffusion path at the electrode-electrolyte interface and helps enhance the overall electrochemical performance. As a freestanding electrode for supercapacitors, it has a high specific capacitance of 1419 F g−1 at 1 A g−1 and good cycling life with capacitance retention of approximately 88.5% after 10,000 cycles. The Ni–Fe–O/NPC@PCNFs-400//Fe2O3/NPC@PCNFs asymmetric supercapacitor (ASC) achieves a high energy density of 41.3 Wh kg−1 at a power density of 892.2 W kg−1 with a long cycle of life (20,000 cycles) and a high rate capability (78.6%), indicating its potential applications.

Novel one-step synthesis for 3-D four-pointed micro-star of quaternary metal (Mo–V–Mn–Ag) oxide electrode for asymmetric supercapacitor

An intention of the present work is to synthesize a quaternary metal oxide by a simple and cost-effective method. MoVMnAg-oxide@Ni-foam is synthesised by one-step hydrothermal method. The as-deposited MoVMnAg-oxide sample is systematically examined through XRD, FESEM, EDS-mapping, and TEM analysis. The electrochemical performance of an MoVMnAg@Ni-foam electrode is tested using CV, GCD, and EIS techniques. MoVMnAg-oxide@Ni-foam has a considerable high areal capacitance of 651 mFcm−2 with 0.13 mWhcm−2 energy at 1.8 mWcm−2 power density in 1 M KOH electrolyte calculated from GCD curves. Also, the electrode shows a diffusion coefficient of 1.52 × 10−7 cm2s−1 along with 91 % of diffusive-controlled contribution and a b-value of 0.51, which depicts faradaic charge storage mechanism. An assembled asymmetric supercapacitor device (MoVMnAg@Ni-foam//AC) delivers an areal capacitance of 312 mFcm−2 with 0.37 mWcm−2 power density at 1 mAcm−2 current density within 0 – 1.5 V voltage window. The asymmetric device showed cyclability and coulombic efficiency of 80.3% and 95% respectively measured up to 10,000 GCD cycles. These results demonstrate the deposition of quaternary metal oxide directly on Ni-foam showing highly competitive electrochemical performance so that they can be utilized in energy storage applications.

Three-dimensional core-shell niobium-metal organic framework@carbon nanofiber mat as a binder-free positive electrode for asymmetric supercapacitor

The metal-organic-frameworks (MOFs) have attracted considerable attention as potential electrode materials for energy storage devices. In the present work, niobium(pyridine-2,6-dicarboxylic acid) MOFs (Nb(PDCA)MOFs) are grown on the surface of electrospun porous carbon nanofiber (CNF) via in-situ solvothermal process. As prepared Nb(PDCA)MOF@CNF hybrid mats were characterized and used as working electrode for supercapacitor applications. To find out ideal electrolyte, the electrochemical characteristics of the Nb(PDCA)MOF@CNF electrode were investigated in different electrolytes such as 3 KOH and 1 M LiCl. The hybrid electrode delivered greater specific capacitance in KOH electrolyte, i.e., 1248.8 F/g at 0.5 A/g, compared to LiCl electrolyte (816.8 F/g), while it has a more stable cycling performance in LiCl electrolyte. The asymmetric supercapacitors (ASCs) were constructed with the as-prepared binder-free Nb(PDCA)MOF@CNF mat as a cathode and the CNF as an anode and investigated their electrochemical properties in both the electrolytes. The higher specific capacitance was achieved for the KOH electrolyte-based ASC. However, the LiCl electrolyte-based ASC delivered superior energy density (64.24 Wh kg−1) and greater cycling stability (98.3 % after 4000 cycles) compared to ASC in KOH electrolyte. The ionic conductivity, chemical nature, and hydrated ionic radius of the electrolyte were found to be important factors to the electrochemical performance of the ASC device.

A new ZnO-ZnS-CdS heterostructure on Ni substrate: A binder-free electrode for advanced asymmetric supercapacitors with improved performance

ZnO is an appealing electrode material for supercapacitors due to its high capacitance, low cost, environmental friendliness, and good electrochemical reversibility. In this paper, we present the synthesis of a newly designed ZnO covered with ZnS and paired with CdS to produce a ternary heterostructure. According to the morphological research, ZnO has an urchin-like shape coated with ZnS and CdS nanoparticles on the surface with no undesired by-product residues, which improves the surface functionalities. First, we combined ZnO and ZnS to make a binary nanocomposite that outperformed its bulk equivalent ZnO by 322 mAh g−1 at 175 mAh g−1 during the charge-discharge process when a low current flow of 1 A g−1 was used. Meanwhile, the synergistic effect of multiple components, a new class of ternary ZnO-ZnS-CdS heterostructure was developed which effectively improved the electrochemical properties of the individual constituents, e.g., a capacity of 434 mAh g−1, and charged transfer kinetics (over pristine ZnO, and ZnO-ZnS electrodes). Inspired from the good capacitive behavior in a three-electrode mode, we further assembled an ASC that exhibits exceptional energy-storage performance of 36 Wh kg−1, 5422 W kg−1 after adding an optimal voltage (1.8 V), and retain only ∼91% at a higher current response. Last but not least, compositing is a vital strategy to boost the overall capacitive performance of the nanomaterials.

Facile synthesis of flower-like Bi2O3 as an efficient electrode for high performance asymmetric supercapacitor

Herein, we report a facile, economic, efficient and binder-free strategy to synthesize a flower-like Bi2O3 thin films on flexible stainless steel mesh (FSSM) substrates by rotational chemical bath deposition (R-CBD) approach. The flower-like Bi2O3/FSSM exhibits a monoclinic α-Bi2O3 phase demonstrating the mesoporous nature with a 58.69 m2 g−1 specific surface area. The Bi2O3/FSSM electrode exhibits specific capacitance of 421.76 F g−1 and specific capacity of 674.8 C g−1 at 10 mA cm−2 current density, remarkable cycle stability (60% up to 1000 cycles), and high energy density (149.95 Wh kg−1) with power density (963.85 W kg−1) in 6 M KOH electrolyte. The results indicate that the 6 M KOH is optimized concentration for Bi2O3/FSSM electrodes. An aqueous asymmetric supercapacitor (ASC) device is fabricated by activated carbon (AC) as cathode and Bi2O3/FSSM as an anode. The assembled Bi2O3||AC ASC device exhibits a specific capacitance of 36.37 F g−1 at a current density of 1 mA cm−2 with the energy density (ED) of 18.24 Wh kg−1 at a power density (PD) of 1008.67 W kg−1 and 83.67% capacitance retention after 1000 cycles at the current density of 2 mA cm−2. The derived Bi2O3/FSSM served as a binder-free electrode that provides potential application for electrochemical energy storage devices.

Preparation and Application of Co3O4/Reduced Graphene Oxide/Ni Foam as High-Performance Asymmetric Supercapacitor Electrodes

Preparation and Application of Co3O4/Reduced Graphene Oxide/Ni Foam as High-Performance Asymmetric Supercapacitor Electrodes

2D-2D nanohybrids of Ni–Cr-layered double hydroxide and graphene oxide nanosheets: Electrode for hybrid asymmetric supercapacitors

• 2D graphene oxide (GO) nanosheets are employed to improve the electrode performance of layer double hydroxide (LDH). • Nanohybrids of Ni–Cr-LDH and GO nanosheets (NCG) are prepared via electrostatic self-assembly method. • NCG nanohybrids enables self-assembly with high surface area, mesoporous morphology, high electrical conductivity, and high charge transfer kinetics. • The aqueous hybrid supercapacitors device displays high energy density (ED) of 51.85 Wh kg –1 and power density (PD) of 1.34 kW kg –1 . • All-solid-state hybrid supercapacitor displays exceptional ED of 38.51 Wh kg–1 and PD of 1.33 kW kg –1 Nanohybrids of 2D Ni–Cr-layered double hydroxide (Ni–Cr-LDH) and graphene oxide (GO) nanosheets (Ni–Cr-LDH–GO) are prepared by electrostatic self-assembly between cationic Ni–Cr-LDH nanosheets and anionic GO nanosheets. Anionic GO nanosheets provide charge-transporting conducting channels leading to remarkably improved electrochemical activity of Ni–Cr-LDH–GO nanohybrid. The unique Ni–Cr-LDH–GO nanohybrid electrodes enable stable electrochemical structure, abundant active electrochemical sites, and fast electron-transporting channels, which play a crucial role in improving the specific capacities, cycle stability, and rate capacity. As a result, Ni–Cr-LDH–GO nanohybrid electrodes demonstrate excellent electrochemical performance with a specific capacity of 815 C g –1 at 1 A g –1 , superior to pristine Ni–Cr-LDH (354 C g –1 ). An aqueous hybrid supercapacitor (AHS) device displays outstanding electrochemical performance with improved energy density (ED) of 51.85 Wh kg –1 and power density (PD) of 1.34 kW kg –1 . An all-solid-state hybrid supercapacitor (ASSHS) displays ED of 38.51 Wh kg –1 and PD of 1.33 kW kg –1 . Furthermore, AHS and ASSHS show excellent cycling stability of 89% and 86% capacitance retention after 10,000 galvanostatic charge/discharge (GCD) cycles, respectively. The present exfoliation-restacking strategy provides a useful method for developing a 2D-2D Ni–Cr-LDH–GO structure for a highly active hybrid-type supercapacitor structure. Exfoliation-reassembly strategy is use to synthesize 2D-2D Ni–Cr-LDH–GO nanohybrids. Owing to the high surface area and high electrical conductivity, Ni–Cr-LDH–GO nanohybrids demonstrated excellent electrochemical performance as a redox electrode in hybrid asymmetric supercapacitor.

Reduced graphene oxide/hexagonal boron nitride-based composite as a positive electrode in asymmetric supercapacitors

Reduced graphene oxide/hexagonal boron nitride-based composite as a positive electrode in asymmetric supercapacitors

RGO-loaded double phase Mo-doped NiS for enhanced battery-type energy storage in hybrid supercapacitors

The Mo-doped NiS/rGO composite was obtained by vulcanization of NiMoO4 and morphology adjustment by GO. A nanosheet-like structure was demonstrated in the composite, which was assembled by double-phase Mo-doped NiS (Mo-NiS) nanodots loading on reduced graphene oxide (rGO) nanosheets. The doping of Mo and the resultant synergistic effect between Mo and Ni can offer the bimetallic sulfide of Mo-NiS with higher capacity output and enhanced cycle stability. The surface oxygen-containing functional groups of GO provide abundant nucleation centers for the uniform loading of Mo-NiS nanodot during synthesis, and the resultant rGO sheets in the final composite ensures continuous electron transport and promoted ionic exchange for Mo-NiS. Besides, the Mo-NiS nanoparticles loaded on the surface of rGO can also inhibit its stacking and form a highly integrated composite structure. The synergistic effect of Mo-doping, double-phase NiS and conductive rGO substrates attributed to the high specific capacity output (1664.7 C g−1 at 1 A g−1), long cycle life and excellent rate performance in the final composite. The Mo-NiS/rGO composite was also applied as a battery-type electrode in asymmetric supercapacitors (ASCs), which showed acceptable performance for potential practicability, including attractable energy densities and power densities, as well as impressive cyclic ability with large capacity retention of 90.3% in 7000 cycles.

Both MOFs-derived Fe-Co-Ni ternary hydroxide positive and Fe2O3/reduced graphene oxide negative electrode for asymmetric supercapacitors

To design and construct high-performance asymmetric supercapacitors (ASC), we use the same Fe-based metal-organic framework (MIL-88A) as the precursor for the first time to prepare iron-cobalt-nickel ternary metal hydroxides (Fe-Co-Ni-OH) and Fe2O3 compounded with reduced graphene oxide (Fe2O3/RGO-1). As a positive electrode, Fe-Co-Ni-OH has a specific capacitance of 1065 F g−1 at 1 A g−1 and exhibits excellent rate performance and cycle stability due to its unique spindle-like structure of the surface growth nanosheets and the synergistic effect between the three metals. The introduction of RGO effectively connects the independent spindle-like Fe2O3 and enhances the conductivity and structural stability of the material. So that the Fe2O3/RGO-1 negative electrode has a specific capacitance of 734 F g−1 at 1 A g−1, and its cycle stability is significantly improved compared with the single Fe2O3 (increasing from 64 % to 85 %). The constructed Fe-Co-Ni-OH//Fe2O3/RGO-1 ASC possesses a satisfactory energy density of 43.11 Wh kg−1 at a power density of 800 W kg−1, which is superior to parts constructed with similar material compositions in the same period. This research provides a new perspective for developing high-performance, low-cost, and environmentally friendly green energy storage devices.

Facile synthesis of NiFe2O4 nanoparticle with carbon nanotube composite electrodes for high-performance asymmetric supercapacitor

The supercapacitor (SCs) is being developed as a cost-effective and efficient energy storage device. Any synergistic impact on binary metal oxide with a CNT composite has been regarded as the desired technique to increase energy storage in recent studies. Herein, we prepared spinel NiFe2O4 enclosed carbon nanotube (CNT) nanocomposites using chemical approach. The physiochemical characteristics of the prepared NiFe2O4/CNT nanocomposite and NiFe2O4 nanoparticle were studied using a variable of analytical techniques. The spinel NiFe2O4/CNT nanocomposite and NiFe2O4 nanoparticle modified electrode were then examined in a 2 M KOH electrolyte using a three-electrode setup. In particular, the specific capacitance of the spinel NiFe2O4/CNT nanocomposite modified single electrode was 670 F g−1 (CV) and 343 F g−1 (GCD) with retention of 89.16% after 5000 cycles, respectively. Furthermore, the specific capacitance of the spinel NiFe2O4/CNT nanocomposite as a cathode and activated carbon as an anode of a two-electrode device was 118.36 F g−1 (CV) and 85.93 F g−1 (GCD), respectively, with an energy density of 23.39 W h kg−1 vs. power density of 466.66 W kg−1. Then the CNT improves the energy storage activity of NiFe2O4 nanocomposite exhibit through exchange stabilization of energy storage performance.

Effect of Annealing on the Defects and Morphology of Cu9S5: Implication for Advanced Electrode for Asymmetric Supercapacitors

Abstract Introduction of defects and engineering of structure play significant roles in improvement on electrochemical performances of copper sulfide (Cu9S5) as a supercapacitors (SCs) electrode. Herein, a hierarchical rose-shaped Cu9S5 is synthesized by using a facile one-step hydrothermal method and subsequently annealed under different atmospheres and time. X-ray photoelectron spectroscopy (XPS) spectra and scanning electron microscopy (SEM) confirm the presence of sulfur vacancies and changes of morphology in Cu9S5 annealed under argon (Ar) for 2 h (Cu9S5-Ar-2h), which exhibit an effective promotion to the surface redox reactions and ion transition ability proved by the electrochemical measurements. Thus, when the Cu9S5-Ar-2h is used as an SCs electrode, it performs the highest specific capacity of 337 C/g at a scanning rate of 5 mV/s, which is nearly four times that of the pristine Cu9S5 (92 C/g). Moreover, an asymmetric supercapacitor using Cu9S5-Ar-2h as a positive electrode and activated carbon as a negative electrode is designed and assembled, which demonstrates a good energy density of 13.2 Wh/kg at a power density of 789.5 W/kg and an outstanding cycling stability of near 100% after 2000 cycles. This work will provide a feasible strategy to construct advanced electrodes based on transition metal sulfides by annealing treatments.