Recent advances in carbon-based electrocatalysts for vanadium redox flow battery: Mechanisms, properties, and perspectives

Vanadium redox flow battery (VRFB) has the advantages of long life, high energy efficiency, safety, and environmental protection, so it has become an excellent energy storage system today. Electrode provides place for redox reactions, which has a significant impact on the performance of VRFB. At present, carbon materials are the most popular electrode materials for VRFB. However, original carbon materials have some problems such as poor electrochemical activity and hydrophilic properties, so they need to be properly modified before use. The introduction of carbon-based catalysts is an excellent way to improve electrode performance. In this paper, the latest progress of carbon-based materials as VRFB electrocatalysts was reviewed, including fullerenes, carbon dots, carbon nanotubes, carbon nanofibers, graphene, biomass carbon, carbon-carbon composite, and other carbon materials. At the same time, modification methods, catalytic mechanism, and electrochemical performance of different carbon-based electrocatalysts were discussed. Finally, applications and challenges of carbon-based materials in VRFB was summarized, and some suggestions for the future development of carbon-based catalysts were put forward.