Study Of Carbon-based Composite Fiber As Negative Electrode For Vanadium Redox Flow Battery

Vanadium redox flow battery?VRFB?has been focused thanks to its excellent performances such as high efficiency,long cycle life,and environmental friendliness.The electrodes play a crucial role owing to that it provides place for reaction.Recently,electrospinning technique has been applied to prepare carbon nanofiber?CNF?as the electrode for VRFB.V²⁺/V³⁺redox reaction has larger voltage loss,so enhancing its electrochemical kinetics is an efficient way to improve the performance of VRFB.In this paper,composite fibers were prepared and used as negative electrode for VRFB.CNF was developed by electrospinning technique with polyacrylonitrile?PAN?as precursor.Nitrogen-doped CNF?NCNF?,synthesized by liquid phase dispersion and carbonization processes with urea at 800-1000°C,was investigated as negative electrode for VRFB.Nitrogen doping can lead to enhancement of surface defect and hydrophilicity.The results show that NCNF treated at 900°C?CNF-N9?exhibits the best electrochemical performance.TiO₂/CNF composite nanofiber was prepared by electrospinning technique with Ti?OC₄H₉?₄ and PAN as precursor,and used as negative electrode for VRFB.The rutile TiO₂ was uniformly distributed in CNF when TiO₂ content is 20%.The results show that CNF-TiO₂-1.0 exhibits the best electrochemical performance.The result attributed to the synergistic effect between CNF with conductivity and TiO₂ with high electrocatalytic properties.Higher discharge capacity of the cell using CNF-TiO₂-1.0 was obtained.ZrO₂/CNF composite nanofiber was prepared by electrospinning technique with the zirconium oxychloride and PAN as precursors,and used as the negative electrode material of VRFB.The results show that CNF-ZrO₂-18 exhibits the best electrochemical performance.The ZrO₂ contribute to the enhancement of electrocatalytic activity towards V²⁺/V³⁺couple,further promoting the electron and mass transfer.Energy efficiency of the cell using CNF-ZrO₂-18 increases by 8.2%compared with pristine cell.Figure39;Table9;Reference80.