Trimetallic spinel NiCo2-xFexO4 nanobox composites self-supported on rGO as thin-film flexible electrodes for high-performance energy storage applications

Abstract

Flexible electrodes with excellent electrochemical properties have been the hot research subject in order for fabrication of flexible energy storage devices that are required in our mordern society. Nevertheless, conventional flexible carbon-based materials are unsuitable for daily use due to their low capacitance limitations. To address this challenge, we have developed a spinel-structured NiCo_2−xFe_xO₄ (NCFO) electrode material and self-assembled it on rGO to create a flexible electrode material of NCFO@rGO, which exhibits the multi-metal synergistic effect, reduced electron transfer distance and enhanced transfer rate, thereby enhanced energy storage capacity. The NCFO@rGO electrode successfully addresses the demands of flexible energy storage devices by providing both flexibility and high specific capacitance. We performed electrochemical correlation performance tests at current densities of 1, 2, 5, 10, 20, 40, and 60 A g⁻¹, respectively. The electrode exhibits a specific capacitance of 2350 F g⁻¹ at 1 A g⁻¹, with a capacitance retention rate of 85.4 % after 10,000 cycles, indicating excellent electrochemical performance and stability. The NFCOrGO//rGO device demonstrates an impressive energy density of 49.73 Wh kg⁻¹ at a power density of 1233.44 W kg⁻¹.