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.

Disclosed are a polymer electrolyte membrane, a method of manufacturing the membrane, and a membrane-electrode assembly including the membrane. The polymer electrolyte membrane contains a porous support having a plurality of pores, a first layer including a first ion conductor that fills the pores adjoining one surface of the porous support, and a second layer including a second ion conductor that fills the pores adjoining the other surface of the porous support, wherein the first ion conductor and the second ion conductor are different from each other, and one selected from the group consisting of the first layer, the second layer, and a combination thereof includes an organic-based antioxidant.

An anion exchange membrane is made by mixing 2 trifluoroMethyl Ketone [nominal] (1.12 g, 4.53 mmol), 1 BiPhenyl (0.70 g, 4.53 mmol), methylene chloride (3.0 mL), trifluoromethanesulfonic acid (TFSA) (3.0 mL) to produce a pre-polymer. The pre-polymer is then functionalized to produce an anion exchange polymer. The pre-polymer may be functionalized with trimethylamine in solution with water. The pre-polymer may be imbibed into a porous scaffold material, such as expanded polytetrafluoroethylene to produce a composite anion exchange membrane.

The present inventive concept relates to a chemically modified anion exchange membrane and a method of preparing the same and, more particularly, an anion exchange membrane in which sulfonic acid groups in a perfluorinated sulfonic acid electrolyte membrane are substituted with anion conductive groups such as an ammonium group, a phosphonium group, an imidazolium group, a pyridinium group and a sulfonium group, and a method of preparing an anion exchange membrane by chemically modifying sulfonic acid groups in a perfluorinated sulfonic acid electrolyte membrane.

The invention pertains to a process for manufacturing a fluoropolymer hybrid organic/inorganic composite, to fluoropolymer hybrid organic/inorganic composites obtained therefrom and to the use of the same in several fields of use.

An ion exchange membrane includes a layer S including a fluorine-containing polymer having a sulfonic acid group, a layer C including a fluorine-containing polymer having a carboxylic acid group, and a plurality of strengthening materials arranged inside the layer S and functioning as at least one of reinforcement yarn and sacrifice yarn. A and B satisfy following formulas:
B≤240 μm  (1)
2.0≤B/A≤5.0  (2) wherein, when the ion exchange membrane is viewed from the top surface, A represents an average cross-sectional thickness of the membrane measured in pure water for a region, in which the strengthening materials do not exist, and B represents an average cross-sectional thickness of the membrane measured in pure water for a region, in which strands of the reinforcement yarn overlap with each other, and in a region, in which the reinforcement yarn overlaps with the sacrifice yarn.

To provide an ion exchange membrane for alkali chloride electrolysis which has high membrane strength and low membrane resistance, thereby capable of reducing the electrolysis voltage during alkali chloride electrolysis. In this ion exchange membrane (1) for alkali chloride electrolysis, a reinforcing material 20 formed by weaving reinforcing yarns 22 and sacrificial yarns 24 is disposed in a layer (S) 14, and layer (S) 14 has elution portions 28 formed by elution of at least portions of the sacrificial yarns 24. In a cross section perpendicular to reinforcing yarns of the warp, the average distance (d1) from the center of a reinforcing yarn 22 to the center of the adjacent reinforcing yarn 22, the total area (P) obtained by adding the cross-sectional area of an elution portion 28 and the cross-sectional area of a sacrificial yarn 24 remaining in the elution portion 28, the number (n) of elution portions between adjacent reinforcing yarns 22, and the ion exchange capacity of a layer (Sa) located on the most anode side in the layer (S) 14 during alkali chloride electrolysis, are controlled to be within specific ranges, respectively.

To provide a process for producing an ion exchange membrane for electrolysis which has a low membrane resistance and which is capable of reducing the electrolysis voltage during the electrolysis, even if the membrane strength is increased, an ion exchange membrane for electrolysis, a precursor membrane of an ion exchange membrane for electrolysis, and an electrolysis apparatus. In a fluorinated polymer having groups convertible to ion exchange groups, a reinforcing fabric 20A formed by weaving covered yarns 21 each comprising a reinforcing fabric 22 and a sacrificial material covering at least a portion of the outer peripheral surface of the reinforcing yarn 22, to produce a precursor membrane of an ion exchange membrane, and from the precursor membrane, at least a portion of the sacrificial material in the reinforcing fabric is eluted to form a reinforcing material and at the same time, the groups convertible to ion exchange groups are converted to ion exchange groups, to produce an ion exchange membrane for electrolysis.

The present inventive concept relates to a method of preparing an ion-exchange membrane using a chemical modification and an ion-exchange membrane prepared thereby. More specifically, the present inventive concept relates to a method of preparing an ion-exchange membrane, which is characterized by modifying sulfonic acid groups of a perfluorinated sulfonic acid electrolyte membrane with carboxyl groups and includes chlorinating sulfonic acid groups of a perfluorinated sulfonic acid electrolyte membrane; nitrilating the chlorinated electrolyte membrane; and hydrolyzing the nitrilated electrolyte membrane, and an ion-exchange membrane chemically modified thereby.

To provide an ion exchange membrane for alkali chloride electrolysis, which has low membrane resistance and which reduces the electrolysis voltage during alkali chloride electrolysis, even if the spacing between reinforcing yarns is made narrow to increase the membrane strength. This ion exchange membrane 1 for alkali chloride electrolysis comprises a fluoropolymer containing ion exchange groups; a reinforcing material embedded in the fluoropolymer and formed of reinforcing yarns and optionally contained sacrificial yarns; and elution holes of the sacrificial yarns present between the reinforcing yarns, wherein in a cross section perpendicular to the length direction of the reinforcing yarns forming the reinforcing material, the average distance (d1) from the center of a reinforcing yarn 22 to the center of the adjacent reinforcing yarn 22 is from 750 to 1,000 m, the total area (S) obtained by adding the cross-sectional area of an elution hole 28 and the cross-sectional area of a sacrificial yarn 24 remaining in the elution hole 28 is from 500 to 5,000 m.sup.2 per elution hole, and the number n of elution holes 28 between adjacent reinforcing yarns 22 is from 4 to 6.