Doping engineering strategies for electrodes and catalysts in vanadium redox flow battery

Vanadium redox flow battery (VRFB) has a wide range of application in energy storage systems due to the large energy storage capacity and stable performance. At present, the development of VRFB still has a series of urgent problems need to be solved for instance low electrochemical activity and poor hydrophilicity of electrodes. Doping engineering is a simple and efficient strategy to improve electrodes performance. After adopting doping engineering strategies, the reactive active sites of the material are increased. The charge density of the surface is redistributed and the hydrophilicity is significantly improved. In this paper, the doping engineering strategies are reviewed from single doping and co-doping. Classifications and discussions are carried out about electrodes and catalysts. By comparing the difference of doping methods and performance, the research progresses of doping engineering strategies are summarized, and the future directions of electrodes development are proposed.