Hybrid Electrodes For Supercapacitors Research Articles

Facile synthesis of high-performance free-standing hierarchically porous NiO/Bi@Bi2O3 hybrid electrode for supercapacitors

By tactfully utilizing the different chemical characteristics of Bi and Ni element in the electrodeposition process, this work successfully designs a novel free-standing NiO/Bi@Bi2O3 hybrid electrode with dual electroactive components (NiO and Bi@Bi2O3) and hierarchically porous structure. After co-electrodeposition, the porous Bi metal as a conductive skeleton can effectively improve the electrical conductivity of the electrode. Moreover, Bi2O3 and NiO have synergistic effects by modifying the electronic structure. The newly developed bimetallic NiO/Bi@Bi2O3 hybrid electrode exhibits high volumetric capacitance value of 1166.67 F cm−3, which is attributed to the dual advantages of structure and composition. This work provides a new idea for the design of high-performance transition metal oxide-based electrodes.

One-Step laser induced molybdenum carbide/graphene hybrid electrode for supercapacitor

Transition metal carbides (TMCs) have garnered significant attention in various energy applications owing to their outstanding conductive and electrochemical properties. Despite these advantages, challenges persist in terms of non-toxicity and efficient fabrication methods. In this study, a Mo3C2/laser-induced graphene (LIG) heterostructure was synthesized via one-step CO2 laser induced conversion process. The specific area capacitance of the Mo3C2/LIG hybrid electrode reached 23.5 mF cm−2, which is 2.5 times higher than that of pure Mo3C2 and 9 times greater than pure LIG electrodes. Moreover, the hybrid electrode exhibited robust cycling stability, maintaining 98.4 % of its initial capacitance after 10,000 charge–discharge cycles. Theoretical simulation also revealed superior hydrogen adsorption and high electrical conductivity of the Mo3C2/LIG hybrid electrode. This work presents a promising approach for developing advanced molybdenum carbide-based composites and offers an alternative strategy for enhancing the electrochemical performance of capacitive electrodes.

Facile controllable sequential electrochemical in-situ synthesis of Fe3O4/PPY hybrid electrode for supercapacitor

In this work, a facile sequential electrochemical synthesis strategy is employed for the precisely controlled in situ polymerization of pyrrole on an iron oxide substrate in the oxalic acid system. The use of porous iron oxide as a template allows for the modification of polypyrrole to create a large conductive network while preserving the integrity of the substrate. This process improves the poor conductivity of conventional metal oxides, allowing for the synthesis of a Fe3O4/PPY hybrid electrode material. The experiments elucidated the mechanism of pyrrole surface morphology coupled with the deposition amount threshold affecting the electrode performance. This was achieved by elucidating the regulation laws of key deposition process parameters (pyrrole monomer concentration, scanning rate, and number of cycles) on the diffusion and oxidation behaviors of pyrrole during the continuous polymerization process. Furthermore, the electrochemical behaviors of the Fe3O4/PPY hybrid electrode were better resolved. The results demonstrate that the deposition amount of PPY on the Fe3O4/PPY hybrid electrode material is within the optimized threshold (1 × 10−6∼3 × 10−6 g), exhibiting a regular and uniform surface morphology with no agglomeration, which indicates a competitive specific capacitance (215.12 mF cm−2 at 1.1 mA cm−2). This strategy of structure-modulated synergistic functional hybridization offers a new approach for designing efficient binder-free hybridized electrode materials.

Theoretical and Experimental Investigation of In Situ Grown MOF‐Derived Oriented Zr‐Mn‐oxide and Solution‐Free CuO as Hybrid Electrode for Supercapacitors

AbstractRecently metal‐organic framework (MOF) derived electrode materials have grown considerable research interest in the field of supercapacitor (SC) technology. Herein, MOF‐derived Zr‐Mn‐oxide is successively combined with solution‐free CuO nanowires not only to avoid the structural limitations of MOF but also to fabricate a positive‐negative hybrid electrode material. The MOF‐derived mixed metal oxide prepared through in situ fabrication allows the uniform and unidirectional growth of oriented Zr‐Mn‐oxide@CuO@Cu. The hybrid electrode exhibited over 100% stability after 20,000 cycles in a three‐electrode setup with a wide potential window range of 1.2 V (−0.6 to 0.6 V). Further, the obtained Zr‐Mn‐oxide@CuO@Cu hybrid electrode exhibited 14.1‐ and 5.5‐fold higher capacity over its MOF‐derived Zr‐Mn‐oxide counterpart (−0.6 to 0.1 V) and CuO (0.0 to 0.5 V), respectively. Additionally, the hybrid device with hybrid Zr‐Mn‐oxide@CuO@Cu as the positive electrode and reduced graphene oxide as the negative electrode also displayed promising energy and power densities. Furthermore, density functional theory calculations are employed to study the hybrid electrode material's properties. Overall, the unidirectional and vertically aligned MOF‐derived Zr‐Mn‐oxide@CuO@Cu hybrid electrode material with notable electrochemical performance can be useful for the fabrication of next‐generation supercapacitor electrodes.

Improved electrochemical performance of nickel cobaltite/ multi-walled carbon nanotube composite as a hybrid electrode for supercapacitors

Metal oxide and carbon nanotubes (CNT) interactions are deep-seated to activate high energy storage ability in energy storage devices. In the present study, NiCo2O4/MWCNT composite is synthesized by the sonochemical method and employed as a hybrid electrode in supercapacitors. The NiCo2O4/MWCNT hybrid electrode delivers a specific capacitance of 418.1 F g−1 (or specific capacity 57.22 mAh g−1) at 2 A g−1 in 6 M KOH electrolyte, which is more than two and half times higher than pristine NiCo2O4. Furthermore, the hybrid electrode displays the high-rate capability (73.1% @10A g−1) and cycling stability (95.2% after 2000 charge-discharge cycles) owing to improved electrical conductivity, low charge transfer resistance, and the good synergistic effect that emerges due to complementary effect. These remarkable electrochemical properties suggest that NiCo2O4/MWCNT composite expected to be a note-worthy supercapacitor electrode material.

Design bifunctional vanadium carbide embedded in mesoporous carbon electrode for supercapacitor and dye-sensitized solar cell

Vanadium carbide embedded in mesoporous carbon (VC–MC) is prepared using an in-situ synthesis method as hybrid electrode for supercapacitor. The electrochemical performance of the VC and VC–MC electrodes are analyzed and compared through a combination of cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy measurements in 1 M H2SO4 aqueous electrolyte. The introduced mesoporous structure of the hybrid electrode provides optimized conducting pathways for electrons and protons, thus improving the capacitive performance of VC–MC electrode compared to pristine VC electrode. The synthesized VC–MC electrode achieves a specific capacitance up to 191.2 F g−1, which is significantly higher than the pristine VC electrode (95.6 F g−1). Moreover, the VC–MC hybrid electrode exhibits an excellent cycle performance with 89.5% capacitance retention after 10,000 charge–discharge cycles, considerably higher than the pristine VC electrode. Apparently, the VC–MC hybrid electrode which shows desirable capacitive performance, excellent stability and enhanced electrochemical properties can be attributable to the combination of the advantages possessed by MC and VC. Moreover, VC–MC was applied as counter electrode in flexible dye-sensitized solar cell which generate power conversion efficiencies of 6.50%, much higher than those of the devices using VC and MC counter electrodes (4.14% and 5.28%).

Ammonium decavanadate nanodots/reduced graphene oxide nanoribbon as “inorganic-organic” hybrid electrode for high potential aqueous symmetric supercapacitors

The issue of relatively low operating potential window in aqueous supercapacitors is usually conquered by fabrication of asymmetric devices. To achieve the same in symmetric cells, electrodes with high electrochemical activity and wide working potential are needed. Herein, we report a strategy to extend the operating potential by utilizing ammonium decavanadate-holey reduced graphene oxide nanoribbons (rGONR-ADV) as hybrid electrode for supercapacitors. Besides high charge storage, use of redox-active ADV in hybrid provides a large overpotential towards water reduction, enabling wide potential window. The nano hybrids are synthesized at three different temperatures (140 °C, 160 °C, 180 °C) where rGONR-ADV 160 shows unsurpassed performance (1186 F g−1 @ 1 A g−1) owing to the optimized synergistic effect, highly electroactive surface area and improved ionic diffusion. The rGONR-ADV 160‖rGONR-ADV 160 cell displays high specific capacitance (406 F g−1 @ 0.5 A g−1), decent cycling stability (83% after 5000 cycles) with high energy/power density (120.2 Wh kg−1 and 1624.14 W kg−1). Interestingly, this device works well up to 1.5 V in 1 M H2SO4 i.e. well beyond thermodynamic limit of water decomposition. Present study illustrates the performance of polyoxometalates based hybrid electrode for high potential aqueous supercapacitors and energy density for practical applications.

Polyaniline-modified renewable biocarbon composites as an efficient hybrid electrode for supercapacitors

Polyaniline-modified renewable biocarbon (ACPANI) composites were prepared via static low-temperature in situ polymerization of aniline monomers on the biomass-based porous biocarbon (AC) that was derived from watermelon rind. In the ACPANI composites, the AC biocarbon was served as a three-dimensional supporting skeleton for polyaniline (PANI) to provide a large accessible surface area, and PANI was used to improve their electrochemical performances. The porous AC biocarbon was coated with nanofibrous arrays of PANI via electrostatic interaction and van der Waals forces. The ACPANI-2 composite that obtained with an AC/aniline mass ratio of 20:80 exhibited an excellent electrochemical performance as a hybrid electrode for supercapacitor. A superb specific capacitance of 520 F g−1 for ACPANI-2 was achieved at a current density of 1 A g−1, and a high cycling stability with a retention rate of capacitance of 71.2% after 5000 cycles was confirmed. Furthermore, an asymmetric supercapacitor using ACPANI-2 as a positive electrode assembled with the AC negative electrode acquired a cell voltage of 1.4 V and a high energy density of 29.3 Wh kg−1. Therefore, the ACPANI composite is suggested to be a promising candidate for electrochemical supercapacitor.

Hemispherical flower-like N-doped porous carbon/NiCo2O4 hybrid electrode for supercapacitors

The N-doped porous carbon/NiCo2O4 (NPC/NiCo2O4) substance is designed and synthesized via hydrothermal treatment, polymerization, carbonization, activation, and chemical bath deposition. The as-prepared NPC/NiCo2O4 holds hemispherical flower-like structure that consists of two things: a porous bowl-shaped NPC at the inside, and sheet NiCo2O4 at the whole outside, in which NPC works as a scaffold for NiCo2O4 to restrain NiCo2O4 nanosheets from aggregation in the synthesis process and NiCo2O4 acts as a capacitive coating layer, and causing a synergic effect. The composite electrode has a specific capacitance of 948.30 F g−1 at a current density of 1 A g−1, enhanced rate capability (727.43 F g−1 at 16 A g−1) and good conductivity. Additionally, NPC/NiCo2O4 reaches a desirable cycling stability (87.4% capacitance retention after 2000 cycles even at a high current density of 10 A g−1), suggesting a hopeful electrode material for the electrochemical supercapacitors.

Mesoporous silica wrapped with graphene oxide-conducting PANI nanowires as a novel hybrid electrode for supercapacitor

A high charge-carrier transport is an important aim in the synthesis of nanostructures for an effective supercapacitor. This article describes a methodology to prepare mesoporous silica nanoparticles (MSNs) wrapped with graphene oxide (GO) together with conducting polyaniline (PANI) wires. The morphology and chemical structure of the prepared samples have been tested by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and X-ray diffraction (XRD), whereas the stability and electrostatic interaction of the structures have been verified by thermogravimetric analysis (TGA) and Fourier-transform infrared (FT-IR) spectroscopy, respectively. The supercapacitive behaviour of these nanocomposites has been analysed by cyclic voltammetry (CV), charge–discharge tests, and electrochemical impedance spectroscopy (EIS). Compared with pristine MSNs and PANI, the 20%-GO@MSNs/PANI nanocomposite had the highest specific capacitance, reaching 412 F g−1. The nanocomposite structure maximizes the synergy between mesoporous metal oxide, conducting PANI, and GO, yielding a significantly enhanced specific capacitance, rapid charge–discharge rates, and good cycling stability of the resulting device. The wrapping with GO prevents the structural breakdown and acts as a highly conductive pathway by bridging the individual particles, whereas the MSNs nanoparticles greatly enlarge the specific surface area to facilitate ion transport and charge transfer throughout the cycling performance of supercapacitor. The approach adopted in this article can be applied for preparing similar novel functional materials in future for electrochemical applications.

Dip time-dependent SILAR synthesis and electrochemical study of highly flexible PPy-Cu(OH)2 hybrid electrodes for supercapacitors

The effect of dip time variations on electrochemical performance of polypyrrole (PPy)-copper hydroxide hybrid thin-film electrodes was studied well in depth. Synthesis was carried out using a successive ionic layer adsorption and reaction (SILAR) method via an aqueous route, using 0.1 M pyrrole, 0.1 M Cu(NO3)2, and H2O2. The electrochemical analysis was made by using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) analysis, and electrochemical impedance spectroscopy (EIS). Scanning electron microscopy (SEM) image of optimized electrode shows nanolamellae-like structures. The characteristic peak observed in Fourier transform infrared (FTIR) analysis at 1558 cm−1 validates the existence of PPy in hybrid electrode material, while the peaks observed at 21.5° and 44.5° in X-ray diffraction (XRD) patterns are evidence for triclinic Cu(OH)2. The observed maximum values of specific capacitance (SC), specific power (SP), specific energy (SE), and coulombic efficiency (η) of the optimized electrode are 56.05 F/g, 10.48 Wh/kg, 11.11 kW/kg, and 46.47%, respectively. For originality and value, the SILAR synthesis of PPy-Cu(OH)2 hybrid thin-film electrodes was carried out for the very first time. Synthesized electrodes showed improved surface structures and electrochemical stability than the pristine PPy electrodes which are necessary for the supercapacitive applications.

Low resistance VFG-Microporous hybrid Al-based electrodes for supercapacitors

It is a challenge to find low-cost graphene-based Al electrodes with a low resistance for a high-performance supercapacitors. For this purpose, we have developed new 3D hybrid structure electrodes composed of vertically oriented few-layer graphene (VFG) grown in situ on Al foil with a microporous structure (VFG/3D-Al). The 3D VFG-Microporous hybrid structured electrode shows a higher specific capacitance than that of a conventional VFG/plane-Al electrode in both aqueous and organic electrolytes. Furthermore, the VFG shows excellent wettability in organic electrolytes, whereby the effective reaction area between the VFG and electrolyte is higher than that in aqueous electrolytes. Thus, the VFG/3D-Al electrode exhibits a high specific capacitance of 1398μF/cm2 (the volumetric specific capacitance up to 139F/cm3) in organic electrolytes, and retains over 90% capacitance after 12,000 cycles. Moreover, the interface of the VFG/Al is modified and shows low contact resistance because the oxide film at the Al surface is removed by plasma etching and Al4C3 is formed at the interface of VFG/Al. This work paves a feasible pathway for the preparation of low-resistance VFG/3D-Al hybrid electrodes for supercapacitors.

Improved electrochemical performances of polyaniline by graphitized mesoporus carbon: Hybrid electrode for supercapacitor

ABSTRACTIn this work, graphitized mesoporus carbon (GMC) was used to increase the specific capacitance and cycle stability of polyaniline (PANI). Hybrid material of polyaniline‐graphitized mesoporus carbon (GMCP) was prepared by in situ chemical polymerization of aniline in presence of sulphuric acid using ammonium persulfate oxidant with various amounts of GMC. Formation of hybrid sample was confirmed from X‐ray diffraction, and the composite sample was stable up to 250°C. Morphology, crystalline nature, and electrochemical performance of GMCP were compared with that of its individual components, GMC and PANI. GMC showed particle morphology and PANI showed nanofiber morphology. GMCP2 composite showed nanofibrous form of PANI grown on GMC (spherical form) along with PANI nanofibers. Higher crystallinity was obtained for GMCP than that of PANI. Cycling stability of GMCP2 was carried up to 12,000 cycles at 1200 W kg−1 and the retention capacitance was 66% of its original capacitance of 243 F g−1. With the same power density, GMC showed less capacitance value of 53 F g−1 with 92% retention and PANI showed capacitance of 187 F g−1 and it underwent 1500 cycles only. Higher supercapacitor performance was obtained for GMCP composite compared to that of its components, PANI and GMC. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42540.

Characterization of modified SiC@SiO2 nanocables/MnO2 and their potential application as hybrid electrodes for supercapacitors.

In this research, we demonstrate a simple route for preparing SiC@SiO2 core-shell nanocables and furthermore obtain SiC@SiO2 nanocables/MnO2 as hybrid electrodes for supercapacitors using various modified methods. The modified procedure consists of mild modifications using sodium hydroxide as well as UV light irradiation and deposition of MnO2. The morphology and microstructural characteristics of the composites are investigated using XRD, XPS, FE-SEM with EDS and TEM. The results indicate that the surfaces of modified SiC@SiO2 nanocables are uniformly coated with a MnO2 thin layer. The electrochemical behaviors of the hybrid electrodes are systematically measured in a three-electrode system using cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The resultant electrode presents a superb charge storage characteristic with a large specific capacitance of 276.3 F g(-1) at the current density of 0.2 A g(-1). Moreover, the hybrid electrode also displays a long cycle life with a good capacitance retention (∼92.0%) after 1000 CV cycles, exhibiting a promising potential for supercapacitors.