Direct Nitradated Graphite Felt as an Electrode Material for the Vanadium Redox Flow Battery

Abstract

The vanadium redox flow battery (VRFB) is one of the most promising electrochemical energy storage systems for grid support. However, the electrochemical performance of the VRFB should be further improved for successful penetration into the large-scale energy storage system market. Among all the components of the VRFB, the electrode, which provides an active site for the vanadium ion redox reaction, plays an important role in determining the electrochemical properties of the VRFB. In this work, nitrogen-doped graphite felts prepared via a direct nitridation route using NH3 were investigated as electrode materials for the VRFB. The resulting N-doped graphite felt electrode showed much improved voltage efficiency and energy efficiency of 87.1 and 85.0%, respectively, compared to those of pristine graphite felt (82.13 and 79.6%, respectively). These improvements can be attributed to doped nitrogen atoms in the graphite felt electrode acting as an efficient electrocatalyst for the vanadium redox reaction in a VRFB system.