Electrolyte membrane for redox flow secondary battery

The invention relates to an electrolyte membrane for redox flow secondary battery, and aims to provide an electrolyte membrane for redox flow secondary battery. The electrolyte membrane has an excellent ion selective permeability, and is capable of inhibiting the ion permeability of active substances while not affecting the permeability of proton (H+). Moreover, the resistance of the electrolyte membrane is low, and the current efficiency of the electrolyte membrane is excellent. The electrolyte membrane also has an oxidation and degradation resistant performance (hydroxy free radical resistance). The provided electrolyte membrane for redox flow secondary battery comprises fluorine high-molecular electrolyte polymer with a specific structure and a specific amount of alkaline polymer.