Cathodic electrodeposition of VO2 (M) nanoparticles on activated carbon cloth (ACC) for solid-state flexible supercapacitors with a wide voltage window

Due to their unique properties, transition metal oxides have attracted much attention in electrical energy storage devices. Herein, a high-performance VO 2 @ACC nanocomposite is prepared on the surface of annealed activated carbon cloth (ACC) via a more flexible, simpler, and convenient cathodic electrodeposition technique combined with an annealing process. The annealed ACC has significantly increased specific surface area (471.2 m 2 ·g -1 ) and excellent electrochemical properties (1262.0 mF·cm -2 at 0.5 mA·cm -2 ); while the VO 2 @ACC nanocomposite possesses superior electrochemical performances (2522.7 mF·cm -2 at 0.5 mA·cm -2 ). This enhanced electrochemical behavior is attributed to the interconnection of VO 2 (M) nanoparticles, which creates a porous channel structure that effectively facilitates the transport of electrolyte ions. In addition, we find that the assembled asymmetric solid-state flexible supercapacitor (VO 2 @ACC//ACC) exhibited excellent mechanical flexibility, a wide voltage window (2.0 V), a high energy density of 0.447 mWh·cm -2 (at a power density of 1.087 mW·cm -2 ), and outstanding stability (88% capacitance retention after 5000 cycles). This work demonstrates the great potential of VO 2 @ACC electrodes in high-performance energy storage, opening new opportunities for the development of VO 2 -based devices. • Interconnection of VO 2 (M) nanoparticles facilitates ion diffusion. • VO 2 @ACC prepared by cathodic electrodeposition with annealing process. • VO 2 @ACC//ACC with a wide voltage window can be applied to flexible/wearable devices.