Simple electrodeposition of MoO₃ film on carbon cloth for high-performance aqueous symmetric supercapacitors

Herein, a MoO₃ film is directly synthesized on carbon cloth through a simple electrodeposition procedure with an annealing treatment. The clingy MoO₃ film on carbon cloth fibers can speedily transfer electrons by virtue of the superior electrical conductivity of carbon cloth, while the outspread MoO₃ film in the gap between the adjacent carbon cloth fibers can provide abundant channels for the diffusion of Li⁺. The electrochemical properties of the as-fabricated MoO₃ electrode working as the cathode and anode materials are systematically studied, respectively. The specific capacitances of the MoO₃ electrode within the potential ranges of 0–1.0 V and of −1.0 to 0 V are 603 and 835 F g⁻¹ at 1 A g⁻¹, respectively. The CV kinetic analysis reveals the surface capacitance-dominated charge storage mechanism for the MoO₃ electrode under different potential windows. Moreover, the energy density of the as-assembled 2.0 V MoO₃//MoO₃ aqueous symmetric supercapacitor device can reach up to 78 Wh kg⁻¹ at 1 kW kg⁻¹. Notably, this device exhibits a brilliant lifespan with 98% storage retention after 8000 CV scans at 150 mV s⁻¹. The ease of preparation and outstanding energy storage capability make this newly-assembled aqueous symmetric supercapacitor a highly potential candidate for practical applications.