REDOX FLOW SECONDARY BATTERY AND ELECTROLYTE MEMBRANE FOR REDOX FLOW SECONDARY BATTERIES

摘要

The purpose of the present invention is to provide a redox flow secondary battery which has low electrical resistance and excellent current efficiency in addition to durability. The present invention relates to: an electrolyte membrane for redox flow secondary batteries, which contains an ion exchange resin composition containing a fluorine-based polymer electrolyte, and which has an ion cluster diameter of 1.00-2.95 nm as determined by a small-angle X-ray method in water at 25°C; and a redox flow secondary battery which uses the electrolyte membrane for redox flow secondary batteries.