Proton exchange membrane capable of being used for all-vanadium redox flow battery and preparation method of proton exchange membrane

The invention provides a proton exchange membrane for an all-vanadium redox flow battery, which comprises a proton exchange membrane base membrane, two first nano carbon coatings respectively positioned on the surfaces of two sides of the proton exchange membrane base membrane, and two second nano carbon coatings respectively positioned on the surfaces of the two first nano carbon coatings, the first nano-carbon coating comprises PFSA and a nano-carbon material A, the second nano-carbon coating comprises PFSA and a nano-carbon material B, the nano-carbon material A is selected from one or two of single-walled carbon nanotubes and multi-walled carbon nanotubes, and the nano-carbon material B is conductive carbon black. The ion selectivity and the puncture strength of the proton exchange membrane are greatly improved, the contact resistance between the proton exchange membrane and a carbon felt electrode is reduced, and the cycle life and the energy efficiency of the all-vanadium redox flow battery are favorabl