A composite proton conductive membrane, comprising an inorganic filler having covalently bonded acidic functional groups and a high surface area of at least 150 m.sup.2/g; and a water insoluble ionically conductive polymer. This membrane provides advantages over traditional polymeric proton conductive membranes for redox flow battery, fuel cell, and electrolysis applications include: 1) enhanced proton conductivity/permeance due to the formation of additional nanochannels for proton conducting; 2) improved proton/electrolyte selectivity for redox flow battery application; 3) reduced membrane swelling and gas or electrolyte crossover; 4) improved chemical stability; 5) increased cell operation time with stable performance, and 6) reduced membrane cost.

Provided is a method of producing a resin porous body using a water-insoluble polymer, the method being excellent in terms of simplicity and capable of suppressing formation of a skin layer. A method of producing a resin porous body disclosed herein includes the steps of: preparing a coating liquid in which a water-insoluble polymer is dissolved and insulating particles are dispersed in a mixed solvent containing a good solvent for the water-insoluble polymer and a poor solvent for the water-insoluble polymer; coating the coating liquid on a substrate; and removing the mixed solvent from the coated coating liquid by vaporization. The poor solvent has a boiling point higher than a boiling point of the good solvent. Pores are formed by removing the mixed solvent by vaporization to obtain a porous body.

The present disclosure relates to an electrolyte membrane for fuel cells having improved chemical durability and a method of manufacturing the same. Specifically, the method includes preparing a polymer film, depositing catalyst metal on one surface or opposite surfaces of the polymer film to obtain a reinforcement layer, and impregnating the reinforcement layer with an ionomer to obtain an electrolyte membrane.

The present disclosure relates to an electrolyte membrane for fuel cells having improved chemical durability and a method of manufacturing the same. Specifically, the method includes preparing a polymer film, depositing catalyst metal on one surface or opposite surfaces of the polymer film to obtain a reinforcement layer, and impregnating the reinforcement layer with an ionomer to obtain an electrolyte membrane.

Disclosed is a method of manufacturing an electrolyte membrane for fuel cells. The method includes preparing an electrolyte layer including one or more ion conductive polymers that form a proton movement channel, and permeating a gas from a first surface of the electrolyte layer to a second surface of the electrolyte layer.

Disclosed is a method of manufacturing an electrolyte membrane for fuel cells. The method includes preparing an electrolyte layer including one or more ion conductive polymers that form a proton movement channel, and permeating a gas from a first surface of the electrolyte layer to a second surface of the electrolyte layer.

A proton exchange membrane includes a porous structural framework and a boron-based acid group bonded to the porous structural framework. The porous structural framework may be formed of an amorphous or crystalline inorganic material and/or a synthetic or natural polymer. The boron-based acid group may be a tetravalent boric acid derivative, such as a cyclic boric acid derivative, borospiranic acid, or a borospiranic acid derivative. The boron-based acid group may be the reaction product of boric acid or a boric acid derivative and a poly-hydroxy compound.

To provide an electrolyte membrane that exhibits high proton conductivity even at low humidity, the electrolyte membrane includes a composite membrane including: a microporous polyolefin membrane that has an average pore diameter of 1 to 1000 nm and a porosity of 50 to 90% and that can be impregnated with a solvent having a surface free energy of 28 mJ/m.sup.2 or more, and an electrolyte containing a perfluorosulfonic acid polymer having an EW of 250 to 850 loaded into the pores of the microporous polyolefin membrane, wherein the membrane thickness of the composite membrane is 1 to 20 μm.

To provide an electrolyte membrane that exhibits high proton conductivity even at low humidity, the electrolyte membrane includes a composite membrane including: a microporous polyolefin membrane that has an average pore diameter of 1 to 1000 nm and a porosity of 50 to 90% and that can be impregnated with a solvent having a surface free energy of 28 mJ/m.sup.2 or more, and an electrolyte containing a perfluorosulfonic acid polymer having an EW of 250 to 850 loaded into the pores of the microporous polyolefin membrane, wherein the membrane thickness of the composite membrane is 1 to 20 μm.

A separator for a redox flow battery and a manufacturing method are provided. The separator includes: a porous substrate; and an ionomer coating layer provided on at least one surface of the porous substrate, wherein the ionomer coating layer includes an ion conductive resin containing ion clusters having a diameter in the range of 3 nm<d.sub.c<6 nm, as measured by small-angle X-ray scattering (SAXS) in water at 25° C.