A Hierarchical Multimetal Oxides@Graphene Fabric Electrode with High Energy Density and Robust Cycling Performance for Flexible Supercapacitors

An advanced structure capable of hosting large electrochemical activity with desired balance in ion diffusion kinetics, faradic charge storage, and robust stability is the key to developing high-performance fabric-based electrochemical supercapacitors (FSCs). Herein, we develop a hierarchical multimetal oxides@graphene fabric (Cu-MO@GFF) as a supercapacitor electrode with accelerated ionic diffusion, adsorption energy, faradic redox reaction kinetics, and electrochemical reversibility. As a result, the Cu-MO@GFF presents excellent mass capacitance (534 F g^-1), high rate performance (266 F g^-1 at 10 A g^-1), and good cycle performance (96.9% capacitive retention after 20,000 cycles) in 6 mol L^-1 (M) KOH electrolyte. In addition, the Cu-MO@GFF-based solid-state FSC delivers excellent energy density (11.875 Wh kg^-1), much-improved cyclic stability, and bending capability. On account of the excellent electrochemical behavior, this solid-state FSC can flexibly power various wearable devices (such as luminous tags, bracelets, and wearable watches), which will offer a new avenue for innovating next-generation wearable energy devices.