An electrochemical cell includes a fuel source; an oxidation source; a positive electrode exposed to an electrolyte membrane; a negative electrode exposed to the electrolyte membrane; and the electrolyte membrane positioned between the positive and negative electrodes, the electrolyte membrane including an electron donor material and a shunt material having specific volume percentage of one or more carbon-containing semiconductors that become electronically conductive at a specific shunting onset potential below the cell's open circuit potential.

A bilayer complex proton exchange membrane and a membrane electrode assembly are provided. The bilayer complex proton exchange membrane includes a first complex structure and a second complex structure. The first complex structure includes 0.001-10 wt % of a graphene derivative with two dimension configuration, and 99.999-90 wt % of organic material. The organic material includes polymer material having sulfonic acid group or phosphate group. The second complex structure includes 0.5-30 wt % of inorganic material and 99.5-70 wt % of organic material, wherein a surface area of the inorganic material is 50-3000 m.sup.2/g, and the organic material includes polymer material with sulfonic acid group or phosphate group.

A bilayer complex proton exchange membrane and a membrane electrode assembly are provided. The bilayer complex proton exchange membrane includes a first complex structure and a second complex structure. The first complex structure includes 0.001-10 wt % of a graphene derivative with two dimension configuration, and 99.999-90 wt % of organic material. The organic material includes polymer material having sulfonic acid group or phosphate group. The second complex structure includes 0.5-30 wt % of inorganic material and 99.5-70 wt % of organic material, wherein a surface area of the inorganic material is 50-3000 m.sup.2/g, and the organic material includes polymer material with sulfonic acid group or phosphate group.

Functionalized polymeric binders for electrolyte and electrode compositions include a polymer having a polymer backbone and functional groups. In some embodiments, a polymer includes a non-polar polymer backbone and a functional group that is 0.1 to 5 wt % of the polymer. In some embodiments, a polymer includes a polar backbone and a functional group that is 0.1 to 50% weight percent of the polymer. Also described are composites for electrolyte separators and electrodes that include argyrodite ion conductors and polar polymers.

A fuel cell system includes a fuel cell in which at least one of an anode electrode and a cathode electrode with an electrolyte membrane interposed therebetween from both sides contains a radical inhibitor; a purging device which performs a purging process of purging water in the fuel cell by supplying a purging gas into the fuel cell after a power generation stop request of the fuel cell is issued; and a purging control unit which sets a purging condition of the purging process so as to increase a purging power in stages or continuously as a correlation value correlated with an accumulated amount of the radical inhibitor accumulated in the electrolyte membrane changes with an increase in the accumulated amount.

A fuel cell system includes a fuel cell in which at least one of an anode electrode and a cathode electrode with an electrolyte membrane interposed therebetween from both sides contains a radical inhibitor; a purging device which performs a purging process of purging water in the fuel cell by supplying a purging gas into the fuel cell after a power generation stop request of the fuel cell is issued; and a purging control unit which sets a purging condition of the purging process so as to increase a purging power in stages or continuously as a correlation value correlated with an accumulated amount of the radical inhibitor accumulated in the electrolyte membrane changes with an increase in the accumulated amount.

A fuel cell membrane electrode assembly is provided comprising a polymer electrolyte membrane comprising a first polymer electrolyte and at least one manganese compound; and one or more electrode layers comprising a catalyst and at least one cerium compound. The membrane electrode assembly demonstrates an unexpected combination of durability and performance.

A fuel cell membrane electrode assembly is provided comprising a polymer electrolyte membrane comprising a first polymer electrolyte and at least one manganese compound; and one or more electrode layers comprising a catalyst and at least one cerium compound. The membrane electrode assembly demonstrates an unexpected combination of durability and performance.

A polymer electrolyte membrane includes a fluorinated polymer membrane and a coating layer including a hydrocarbon-based ionomer on at least one surface of the fluorinated polymer membrane. The polymer electrolyte membrane maintains high hydrogen ion conductivity and has improved performance under high temperature and low humidity conditions. A membrane electrode assembly and a fuel cell including the polymer electrolyte membrane are also disclosed.

A polymer electrolyte membrane includes a fluorinated polymer membrane and a coating layer including a hydrocarbon-based ionomer on at least one surface of the fluorinated polymer membrane. The polymer electrolyte membrane maintains high hydrogen ion conductivity and has improved performance under high temperature and low humidity conditions. A membrane electrode assembly and a fuel cell including the polymer electrolyte membrane are also disclosed.