A high-performance ammonia plasma-treated WO3 @carbon felt electrode for vanadium redox flow batteries

Due to the pressing need for harnessing renewable energy, sizable energy storage technologies have become increasingly critical, among which vanadium redox flow batteries (VRFBs) are considered as one of the promising technologies. However, the lack of high-performance electrodes hinders the development of VRFBs. Herein, we report a new ammonia plasma-treated WO 3 @carbon felt as a high-performance electrode for VRFBs. The ammonia plasma introduces not only N-contained functional groups but also oxygen deficiencies on WO 3 , which provide additional active sites and improve the conductivity, leading to high catalysis for both cathodic and anodic vanadium redoxes. As a result, the energy efficiency and the power density of the VRFB increase from 78.9% to 86% and from 365.5 mWcm[Formula: see text] to 389.6 mWcm[Formula: see text], respectively. Moreover, the energy efficiency of composite electrodes remains stable for more than 300 cycles. This study provides a new strategy for designing cost-effective, environmentally friendly, and high-performance electrodes for future VRFBs.