The present disclosure relates to a polymer electrolyte membrane comprising a polymer membrane containing an ion conductor, and a plurality of composite fibers, wherein the composite fiber comprises a core portion continuously formed in the longitudinal direction of the composite fiber and a matrix portion surrounding the core portion, and the core portion contains an ion exchange functional group.

The present disclosure relates to a membrane-electrode assembly for fuel cells and a method of manufacturing the same, and more particularly to a membrane-electrode assembly to which an electrolyte membrane including a cerium oxide and phosphoric acid functionalized graphene oxide is applied, whereby chemical durability and proton conductivity of the membrane-electrode assembly are improved.

The present invention relates to a membrane electrode unit comprising a polymer membrane doped with a mineral acid as well as two electrodes, characterized in that the polymer membrane comprises at least one polymer with at least one nitrogen atom and at least one electrode comprises a catalyst which is formed from at least one precious metal and at least one metal less precious according to the electrochemical series.

The present invention relates to a membrane electrode unit comprising a polymer membrane doped with a mineral acid as well as two electrodes, characterized in that the polymer membrane comprises at least one polymer with at least one nitrogen atom and at least one electrode comprises a catalyst which is formed from at least one precious metal and at least one metal less precious according to the electrochemical series.

A method for producing a liquid composition containing a fluoropolymer having sulfonic acid groups, trivalent cerium ions and water, by (1) irradiating a solution containing at least one cerium compound selected from cerium carbonate, cerium hydroxide and cerium oxide, the fluoropolymer and the water, with light at least partially in a wavelength region from 300 to 400 nm so that the ultraviolet irradiance on the surface of the solution is at least 0.1 mW/cm.sup.2 or (2) adding a reducing agent to a solution containing at least one cerium compound selected from cerium carbonate, cerium hydroxide and cerium oxide, the fluoropolymer and the water.

A method for producing a liquid composition containing a fluoropolymer having sulfonic acid groups, trivalent cerium ions and water, by (1) irradiating a solution containing at least one cerium compound selected from cerium carbonate, cerium hydroxide and cerium oxide, the fluoropolymer and the water, with light at least partially in a wavelength region from 300 to 400 nm so that the ultraviolet irradiance on the surface of the solution is at least 0.1 mW/cm.sup.2 or (2) adding a reducing agent to a solution containing at least one cerium compound selected from cerium carbonate, cerium hydroxide and cerium oxide, the fluoropolymer and the water.

Disclosed are redox flow battery membranes, redox flow batteries incorporating the membranes, and methods of forming the membranes. The membranes include a densified polybenzimidazole gel membrane that is capable of incorporating a high liquid content without loss of structure that is formed according to a process that includes in situ hydrolysis of a polyphosphoric acid solvent followed by densification of the gel membrane. The densified membranes are then imbibed with a redox flow battery supporting electrolyte such as sulfuric acid and can operate at very high ionic conductivities of about 50 mS/cm or greater and with low permeability of redox couple ions, e.g. vanadium ions, of about 10.sup.−7 cm.sup.2/s or less. Redox flow batteries incorporating the membranes can operate at current densities of about 50 mA/cm.sup.2 or greater.

Disclosed are a membrane-electrode assembly and a method for manufacturing the same. The membrane-electrode assembly has durability and proton conductivity which are improved by employing an ion conductive polymer having improved chemical durability and ion conductivity.

The present invention relates to an ion exchange membrane and an energy storage device comprising same, wherein the ion exchange membrane comprises: a polymer membrane comprising an ion conductor; and any one ion permeation inhibiting additive selected from the group consisting of a columnar porous metal oxide, crown ether, a nitrogen-containing cyclic compound, and a mixture thereof. In the ion exchange membrane, the size of a channel through which ions permeate is limited or an additive capable of trapping ions is introduced into an ion movement path, so that the permeation of ions is prevented, leading to the improvement of voltage efficiency and the prevention of deterioration.

A membrane-electrode assembly, a method for manufacturing the membrane-electrode assembly, and a fuel cell including the membrane-electrode assembly are disclosed. The membrane-electrode assembly includes: an ion exchange membrane; catalyst layers disposed on both sides of the ion exchange membrane respectively; and a functional modification layer disposed between the ion exchange membrane and each of the catalyst layers. The membrane-electrode assembly has a low hydrogen permeability without a reduction of hydrogen ion conductivity, has excellent interfacial bonding properties between the catalyst layers and the ion exchange membrane, and has excellent performance and durability under high temperature/low humidity conditions.