High-energy solid-state asymmetric supercapacitor based on nickel vanadium oxide/NG and iron vanadium oxide/NG electrodes

Solid-state supercapacitors (SCs) are well-known as one of the most competitive power sources for modem electronics. However, most of the reported solid-state SCs suffer from low specific capacitance and energy density. Herein, a novel strategy for the synthesis of nickel vanadium oxide (Ni3V2O8) and iron vanadium oxide (Fe2VO4) nanoparticles (NPs) anchored nitrogen doped graphene (NG) for high energy solid-state asymmetric SC (ACS) through a simple and cost-effective hydrothermal technique was demonstrated. SEM and TEM analysis reveals that active Ni3V2O8 and Fe2VO4 NPs with uniform size are anchored on NG sheets. Electrochemical performance of Ni3V2OW8/NG and Fe2VO4/NG electrodes showed that both have ultra-high specific capacitances (similar to 1898 F g(-1) and 590 F g(-1) at current density of 1 A g(-1), respectively), tremendous rate capabilities, and superior cycling stabilities. Most significantly, solid-state ASC consisting of Ni3V2O8/NG as a cathode and Fe2VO4/NG as an anode which achieves a high energy density of similar to 77.2 W h kg(-1) at a power density of 863 W kg(-1) and an ultra-long cycle life (capacitance retention of similar to 83.3% after 20,000 cycles). This study emphasizes the development of a wide variety of energy storage systems for modem electronics.