A High-Performance Asymmetric Supercapacitor Based on Tungsten Oxide Nanoplates and Highly Reduced Graphene Oxide Electrodes.

Tungsten oxide/graphene hybrid-materials are attractive semiconductors for energy-related applications. Herein, we report an asymmetric supercapacitor (ASC, HRG//m-WO 3 ASC), fabricated from monoclinic tungsten oxide (m-WO 3 ) nanoplates as a negative-electrode and highly reduced graphene oxide (HRG) as a positive-electrode material. The supercapacitor performance of the prepared electrodes was evaluated in an aqueous-electrolyte (1M H 2 SO 4 ) using three- and two- electrode systems. The HRG//m-WO 3 ASC exhibits a maximum specific capacitance of 389 F/g at a current density of 0.5 A/g, with an associated high energy density of 93 Wh/kg at a power density of 500 W/kg in a wide 1.6 V operating potential window. In addition, the HRG//m-WO 3 ASC displays long-term cycling-stability, maintaining ~92% of the original specific capacitance after 5000 galvanostatic charge-discharge cycles. The m-WO 3 nanoplates were prepared hydrothermally while HRG was synthesized by a modified Hummers method.