REDOX FLOW SECONDARY BATTERY

摘要

The problem addressed by the present invention is to obtain an electrolyte membrane that, as an electrolyte membrane for a redox flow secondary battery, is able to suppress the ion permeability of an active substance without detracting from proton (H+) permeability, has superior ion-selective permeability, has low electrical resistivity, and has superior current efficiency. The present invention solves the abovementioned problem by means of the electrolyte membrane for a redox flow secondary battery containing a perfluorocarbon sulfonic acid resin having a specific structure and an equivalent weight (EW), and the ion conductivity being adjusted to a predetermined range.