High Performance Solid-State Asymmetric Supercapacitor using Green Synthesized Graphene-WO3 Nanowires Nanocomposite

Development of active materials capable of delivering high specific capacitance is one of the present challenges in supercapacitor applications. Herein, we report a facile and green solvothermal approach to synthesize graphene supported tungsten oxide (WO3) nanowires as an active electrode material. As an active electrode material, the graphene-WO3 nanowire nanocomposite with an optimized weight ratio has shown excellent electrochemical performance with a specific capacitance of 465 F g(-1) at 1 A g(-1) and a good cycling stability of 97.7% specific capacitance retention after 2000 cycles in 0.1 M H2SO4 electrolyte. Furthermore, a solid-state asymmetric supercapacitor (ASC) was fabricated by pairing a graphene-WO3 nanowire nanocomposite as a negative electrode and activated carbon as a positive electrode. The device has delivered an energy density of 26.7 W h kg(-1) at 6 kW kg(-1) power density, and it could retain 25 W h kg(-1) at 6 kW kg(-1) power density after 4000 cycles. The high energy density and excellent capacity retention obtained using a graphene-WO3 nanowire nanocomposite demonstrate that it could be a promising material for the practical application in energy storage devices.