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

Abstract

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