Patent ID: 8802317

Claim:
A polymer electrolyte membrane (PEM) which exhibits a proton conductivity at least in the presence of water, the proton conductivity being sufficient for the operation in a fuel cell, comprising: at least one oxidation protection agent, additives, and a blend of an acid polymer and a base polymer which blend forms acidic and basic domains, wherein the basic polymer is polybenzimidazole (PBI), the acid polymer is perfluorosulfonic acid polymer and the at least one oxidation protection agent is manganese oxide, wherein the perfluorosulfonic acid polymer forms a proton conductive matrix phase, wherein manganese oxide is embedded in the basic domains formed by the polybenzimidazole, wherein the membrane contains water in an amount of 1-10 mol water per mol sulfonic acid groups, and wherein polybenzimidazole (PBI) comprises 0.5 to 8 weight % of the PEM.