| abstract |
This invention provides a solid polymer electrolyte which is low in water absorption, from which no dopant runs out even in pressing, and which is excellent in stability in the presence of water or methanol, proton conductivity and methanol barrier properties, in which an imidazole ring-containing polymer such as a polybenzimidazole compound is doped with an acid in which at least one hydrogen atom of an inorganic acid such as phosphoric acid is substituted by a functional group having a phenyl group by blending the imidazole ring-containing polymer with the acid in a solution using a solvent such as trifluoroacetic acid, preferably at a rate of 1 to 10 molecules of the acid per repeating structure unit of a molecular chain of the imidazole ring-containing polymer, the solid polymer electrolyte. |