A High-Performance Composite Electrode for Vanadium Redox Flow Batteries

A composite electrode composed of reduced graphene oxide-graphite felt (rGO-GF) with excellent electrocatalytic redox reversibility toward V2+/V3+ and VO2+/VO2+ redox couples in vanadium batteries was fabricated by a facile hydrothermal method. Compared with the pristine graphite felt (GF) electrode, the rGO-GF composite electrode possesses abundant oxygen functional groups, high electron conductivity, and outstanding stability. Its corresponding energy efficiency and discharge capacity are significantly increased by 20% and 300%, respectively, at a high current density of 150 mA cm(-2). Moreover, a discharge capacity of 20 A h L-1 is obtained with a higher voltage efficiency (74.5%) and energy efficiency (72.0%), even at a large current density of 200 mA cm(-2). The prepared rGO-GF composite electrode holds great promise as a high-performance electrode for vanadium redox flow battery (VRFB).