Proton conducting electrolytes with cross-linked copolymer additives for use in fuel cells

A proton conducting polymer electrolyte comprising a proton conducting ionomer and a polymetaloxane copolymer additive, wherein the polymetaloxane copolymer additive, prior to addition, comprises (i) cross-linking functional groups and (ii) other functional groups, and wherein, in the proton conducting polymer electrolyte, the ionomer and copolymer additive are covalently bonded or acid-base complexed together at the cross-linking functional groups of the polymetaloxane copolymer, wherein:

• the polymetaloxane copolymer prior to addition comprises a polymerized network of
• a plurality of metal oxide monomers with the cross-linking functional groups and
• a plurality of metal oxide monomers with the other functional groups, in random or block sequence, wherein:
• the metal oxide monomers with the cross-linking functional groups comprise:
• a first metal bonded to at least two oxygen atoms and selected from the group consisting of Si, Ti, Zr, Ce, Ta, and Cr;
• and
• the cross-linking functional groups bonded to the first metal and comprising a functional end group containing nitrogen or oxygen and characterized by a chemical structure selected from the group consisting of —NH2, ═NH, -(aliphatic) —OH, -(aryl)-OH,
• wherein R is a hydrocarbon group;
• and
• the metal oxide monomers with other functional groups comprise:
• a second metal bonded to at least two oxygen atoms and selected from the group consisting of Si, Ti, Zr, Ce, Ta, and Cr;
• and
• the other functional groups bonded to the second metal and selected from the group consisting of:
• i) proton carrier functional groups comprising a functional end group selected from the group consisting of —PO3H2, —COOH, —SO3H, and —SO2NHSO2CF3,
• ii) metal chelating functional groups comprising a functional end group selected from the group consisting of phosphonic acid, bipyridine, phenanthroline, and derivatives thereof, and
• iii) free radical scavenger functional groups comprising a functional end group selected from the group consisting of aminophenyl, hydroxyphenyl and derivatives thereof.