Method for modifying carbon fibers by using beta-PbO2 particles and application of method

The invention discloses a method for modifying carbon fibers by using beta-PbO2 particles and application of the method. The beta-PbO2 particles having single crystal forms are successfully modified on the surface of the carbon fibers by a linear scanning voltage method, so that the particle size is uniform, and the deposition amount is controllable; furthermore, a preparation technology is simple, the cost is low, and the method is suitable for large-scale development and utilization; due to the modification beta-PbO2 particles, the hydrophilicity of the carbon fibers is improved, and the surface active sites are increased; the electrochemical activity to VO /VO redox reaction of a VFB positive electrode is enhanced, so that the exchange current density and the reaction rate constant are obviously increased; a carbon fiber fabric modified by the beta-PbO2 particles is used as a positive electrode material for assembling an all-vanadium redox flow battery; compared with the battery assembled by the non-modified carbon fiber fabric serving as an electrode material, the all-vanadium redox flow battery assembled by the carbon fiber fabric modified by the beta-PbO2 particles has the advantages that the energy conversion efficiency and the power density are obviously improved, and the long-time circulating performance is stable.