Electrolyte membrane for redox flow secondary battery and redox flow secondary battery using the same

摘要

PROBLEM TO BE SOLVED: To provide an electrolyte membrane for a redox flow secondary battery offering excellent selective ion permeability to inhibit the penetration of ions of an active material without impairing proton (H) permeability, and having low electric resistance, excellent current efficiency, and oxidation degradation resistance (hydroxy radical resistance), and a redox flow secondary battery including the same.SOLUTION: The electrolyte membrane for a redox flow secondary battery contains a fluorine-based polyelectrolyte polymer with a specific structure. The electrolyte membrane has a multilayer structure including three or more layers, and the equilibrium moisture content of the outer layers adjacent to a positive electrode or a negative electrode is higher than the equilibrium moisture content of the intermediate layer that is not adjacent to the positive electrode or the negative electrode.