Patent ID: 7879475

Claim:
A solid polymer electrolyte, comprising: a perfluorinated electrolyte having cation exchange groups, and metal ions partially replacing protons of the cation exchange groups, wherein the solid polymer electrolyte has an ion exchange rate with the metal ions of 0.01 to 60%, as represented by Formula (1) below: Ion exchange rate=((number of moles of the metal ions×valence of the metal ions)/total number of moles of the cation exchange groups contained in the perfluorinated electrolyte)×100 (1), wherein the metal ion is at least one metal ion selected from the group consisting of vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), iron (Fe), ruthenium (Ru), nickel (Ni), palladium (Pd), platinum (Pt), neodymium (Nd), praseodymium (Pr), samarium (Sm), cobalt (Co), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), and erbium (Er) ions.