Ion-conductive polymeric materials as electrolytes for fuel cells

A proton-conductive fluoropolymer membrane comprising a structural formula of Mz(ManO3P-PRU)x(Mbn'O3P-R)yEmE’m'•tH2O;

• wherein,
• M is a metal cation selected from the group consisting of Zr, Ti, Sn, Ge, Pb, Hf, Ce, Mo and W;
• Ma and Mb are independently selected from the group consisting of H, NH4, Na, K, Cs, Li, Rb, Mg, Ca, and Sr;
• n and n′ are numbers independently chosen from 0 to 2;
• E and E′ are independently selected from the group consisting of OH, F, (C1-C6)hydrocarbon residues, and (C1-C6) fluorocarbon residues;
• m and m′ are numbers independently chosen from 0 to 6;
• t is a number chosen from 0 to 6;
• •H2O represents the structural formula comprising t number of H2O;
• z is an integer from 1, 2 or 3;
• x is a number from 0.01 to 3;
• y is a number from 0 to 5;
• R is selected from the group consisting of H, OH, O, Cl, and a monovalent (C1-C12)hydrocarbon or fluorocarbon residue;
• -PRU has a formula selected from (V)-(VIII), which is a repeating unit of a homopolymer or a copolymer:
• wavy lines indicate the points of attachment to adjacent repeating units of the polymer;
• ne and nf are independent integers from 0 to 8;
• ng and nh are independent integers from 0 to 3;
• Rf2 and Rf3 are independently F or CF3;
• Ar4 and Ar5 are independently (C3-C24)aromatic or heteroaromatic groups;
• L1 and L2 are independently selected from the group consisting of a direct bond, and a bivalent (C1-C12)hydrocarbon or fluorocarbon residue;
• and
• Lf1 and Lf2 are independently selected from the group consisting of a direct bond, OCF2, OCF2CF2, OCF2CF2CF2, OCF2CF2CF2CF2, and OCF2CF2CF2CF2CF2.

An impregnation method of making a proton-conductive fluoropolymer membrane, comprising

• (a) eliminating the solvent from a solution comprising a fluoropolymer of perfluorophosphonic acid (PFPA);
• (b) mixing the PFPA residue from (a) with a mixture comprising a metal (4+) salt having a cation selected from the group consisting of Zr4+, ZrO2+, Ti4+, Sn4+, Ge4+, Pb4+, Hf4+, Ce4+, Mo4+ and W4+ and an anion, and optionally a phosphonic acid or phosphoric acid in the solvent;
• (c) eliminating the solvent from (b);
• (d) repeating step (a), (b) and/or (c) if necessary.
• wherein, the solvent of (a) is selected from the group consisting of water, phosphoric acid, hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydriodic acid, sulfuric acid, nitric acid, organic solvents and combinations thereof, the PFPA is present at a concentration from 0.001 M to 50 M, preferably from 0.1 M to 1 M;
• and the anion of the metal (4+) salt is a negatively charged ion;
• in (b), the metal (4+) salt is present at a concentration from 0.001 M to 50 M, preferably from 0.1 M to 1 M;
• the phosphonic acid or phosphoric acid, if present, is present at a concentration from 0.001 M to 50 M, preferably from 0.1 M to 1 M;
• and the solvent is selected from the group consisting of water, phosphoric acid, hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydriodic acid, sulfuric acid, nitric acid, organic solvents and combinations thereof.

A mixing method of making a proton-conductive fluoropolymer membrane, comprising

• (a) mixing a fluoropolymer of perfluorophosphonic acid (PFPA), a metal (4+) salt having a cation selected from Zr4+, Ti4+, Sn4+, Ge4+, Pb4+, Hf4+, Ce4+, Mo4+ and W4+ and an anion, and optionally a phosphonic acid or phosphoric acid in a solvent;
• (b) eliminating the solvent from the mixture of (a);
• (c) repeating step (a) and/or (b) if necessary.
• wherein, the solvent of (a) is selected from the group consisting of water, phosphoric acid, hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydriodic acid, sulfuric acid, nitric acid, organic solvents and the combination thereof;
• the PFPA is present at a concentration from 0.001 M to 50 M, preferably from 0.1 M to 1 M;
• the metal (4+) salt is present at a concentration from 0.001 M to 50 M, preferably from 0.1 M to 1 M;
• the anion of the metal (4+) salt is a negatively charged ion;
• and the phosphonic acid or phosphoric acid, if present, is present at a concentration ranges from 0.001 M to 50 M, preferably from 0.1 M to 1 M.