Flow batteries are considered as one of the most promising technologies for large-scale energy storage

due to their inherent safety

long cycle life

environmental friendliness and robust scalability. As the key material of flow batteries

electrodes have a significant influence on battery performance. The research advancements of electrospun carbon nano-fiber electrodes in flow batteries are reviewed. The fabrication principles of electrospun carbon nano-fibers and their influence on the critical fabrication parameters are elucidated. It provides a comprehensive review of preparation methods for electrospun carbon nano-fiber electrodes with controllable structure and chemistry

properties and their effect on battery performance

including microstructural modulation of carbon nano-fibers

heteroatom doping

and catalytic modification. The key of electrode optimization is synergies between electrochemical activity and mass transport of electrodes

which are associated with the active areas and chemistry properties. The microstructure and surface properties of fibers can be controlled by strategies involving fiber porosity or new structural designs. Doping heteroatoms and introducing catalysts can increase the active area and hydrophilicity of the electrodes to promote the electrochemical activity of the electrodes. Lastly

the challenges and future developments of the electrospun carbon nano-fiber electrodes from laboratory preparation to scaling-up are outlined.