It is to provide a membrane/electrode assembly excellent in the power generation characteristics under low or no humidity conditions and under high humidity conditions; and an electrolyte material having a low water content, suitable for a catalyst layer o...

It is to provide an electrolyte material with which an increase in the water content can be suppressed even when the ion exchange capacity of a polymer having repeating units based on a monomer having a dioxolane ring is high; and a membrane/electrode asse...