Carbon-Embedded Ru/NiO-CuO Cathode and rGO/α-Co3O4 Anode for Synergetic Charge Transfer for High-Performance Solid-State Asymmetric Supercapacitors

In this work, an attempt has been made to synthesize a novel heterostructure nanocomposite, C/Ru@NiO-CuO (CRNC) which is suitable for energy storage application. It was chemically synthesized at high-temperature conditions, whose structural features and surface chemistry were characterized by various analytical tools. The CRNC nanocomposite reveals the nanospherical morphology with highly crystalline heterostructure, leading to reliable electrode material-preferred advantages such as good conductivity, high-surface area, and numerous oxidation states for supercapacitor (SC) applications. Composition of high conductivity of carbon and high chemical stability of ternary metal oxides, a heterostructure CRNC electrode is proposed for effective solid-state symmetric and asymmetric battery-type SC. The as-prepared CRNC shows an excellent electrochemical performance at 0.5 A g(-1) in a three-electrode cell configuration, where the specific capacitance value obtained was 318 F g(-1). Having the completion of 5000 galvanostatic charge-discharge (GCD) cycles, the electrode can hold a good capacity retention (86.7%). A solid-state asymmetric supercapacitor (ASC) was constructed by placing the separator between the CRNC and rGO/alpha-Co3O4, which delivers a specific capacitance of 152.5 F g(-1) (at 0.5 A g(-1)) along with 87% capacitance retention after 3500 GCD cycles. Furthermore, the ASC offers energy and power density values as 21.18 W h kg(-1) and 1800 W kg(-1), respectively. The novel CRNC//rGO/alpha-Co3O4 construction implies a good structural stability, long-term cycle stability, very good rate capability, and favorable compatibility. This study reveals that carbon-embedded Ru-doped NiO-CuO nanocomposite electrode exhibits better electrochemical behavior due to the high synergistic effect of ternary metal oxide compared with bimetal oxide. To improve the practical applicability of ASC device, we assembled the device for better flexibility, also demonstrating the extensive advantages and accessibility.