Anion-exchange membranes are useful for electro-membrane processes such as electrodialysis (water desalination, separation of inorganics from organic molecules, separation of specific inorganic ion, etc.), in-situ ion-exchange and ion substitution, electro-deionization for producing ultrapure water, polymer electrolyte membrane for alkaline fuel cell and electrolysis applications. The present invention discloses an acid and base resistant fluorinated hydrocarbon based anion-exchange membrane and its method of preparation thereof. In the first step co-polymerization is carried out between N-isopropylacrylamide and 1-vinylimidazole. In the second step, obtained inter-polymer of isopropylacrylamide-co-vinylimidazole co-polymer is mixed with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) (IA-co-VI/PVDF-co-HFP), which is used for casting membrane film of desired thickness. The obtained casted membrane thin film is quaternized in methyl iodide solution.

The present invention relates to new anion exchange polymers and (blend) membranes made from polymers containing highly fluorinated aromatic groups by means of nucleophilic substitution and processes for their production by means of nucleophilic aromatic substitution and their areas of application in membrane processes, in particular in electrochemical membrane processes such as fuel cells, electrolysis and redox flow batteries.

The present disclosure discloses an asymmetric electrolyte membrane, a membrane electrode assembly including the same, a water electrolysis apparatus including the same and a method for manufacturing the same. More particularly, it discloses an asymmetric electrolyte membrane having a porous layer and a dense layer at the same time, a membrane electrode assembly including the same, a water electrolysis apparatus including the same and a method for manufacturing the same.

Provided are membranes useful for electrochemical or fuel cells. A membrane may be formed of or include a sulfonated polymer whereby the sulfonated polymer is covalently or ionically associated with a multi-nitrogen containing heterocyclic molecule. The resulting membranes possess excellent ion conductivity and selectivity.

To provide an ion exchange membrane for alkali chloride electrolysis which has a low membrane resistance and which is capable of reducing the electrolysis voltage during the alkali chloride electrolysis, while increasing the membrane strength.

An ion exchange membrane 1 for alkali chloride electrolysis wherein a reinforcing material 20 obtained by weaving with reinforcing yarns 22 and sacrificial yarns 24 is embedded in a fluoropolymer having ion exchange groups, the ion exchange membrane 1 comprises elution holes (28) formed by eluting at least a portion of a material of the sacrificial yarns 24, and in a cross section perpendicular to the length direction of the yarns, 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 1,200 μm.sup.2, and the number (n) of elution holes 28 between adjacent reinforcing yarns 22 is at least 10.

An object of the present invention is to provide a redox flow secondary battery being low in the electric resistance and excellent in the current efficiency as well, and further having the durability. The present invention relates to an electrolyte membrane for a redox flow secondary battery, the electrolyte membrane containing an ion-exchange resin composition containing a fluorine-based polyelectrolyte polymer, and having an ion cluster diameter of 1.00 to 2.95 nm as measured in water at 25° C. by a small angle X-ray method, and to a redox flow secondary battery using the electrolyte membrane.

A process for reducing the amount of soluble polymeric fractions in a sulfonyl fluoride polymer. The process comprises contacting the sulfonyl fluoride polymer with a fluorinated fluid followed by separation of the polymer from the fluid. The fluorinated fluid is selected from hydrofluoroethers and hydrofluoropolyethers. The invention further relates to sulfonyl fluoride polymers obtainable by the process and having a heat of fusion not exceeding 4 J/g and containing less than 15% by weight of polymeric fractions having an average content of monomeric units comprising a sulfonyl functional group exceeding 24 mole %. The sulfonyl fluoride polymers so obtained are particularly suitable for the preparation of ionomeric membranes for use in electrochemical devices.

To provide a membrane/electrode assembly excellent in the power generation characteristics in a wide temperature range and a wide humidity range; an electrolyte material suitable for a catalyst layer of the membrane/electrode assembly; and a liquid composition suitable for forming a catalyst layer of the membrane/electrode assembly.

To use an electrolyte material which is formed of a polymer (H) obtained by converting precursor groups in a polymer (F) having structural units (A) based on a perfluoromonomer having a precursor group represented by the formula (g1), structural units (B) represented by the formula (u2), and structural units (C) based on tetrafluoroethylene, wherein the proportion of the structural units (A) is from 8 to 19 mol %, the proportion of the structural units (B) is from 65 to 80 mol %, and the proportion of the structural units (C) is from 1 to 27 mol %, to ion exchange groups.

##STR00001##

A method for producing a fluorosulfonyl group-containing compound to obtain a compound represented by the following formula 5 from a compound represented by the following formula 1 as a starting material and a method for producing a fluorosulfonyl group-containing monomer in which the fluorosulfonyl group-containing compound is used: ##STR00001##
wherein R.sup.1 and R.sup.2 are a C.sub.1-3 alkylene group, and R.sup.F1 and R.sup.F2 are a C.sub.1-3 perfluoroalkylene group.

Ion exchange membranes may comprise a polymeric microporous substrate and a cross-linked ion transferring polymeric layer on the substrate. The cross-linked ion transferring polymeric layer may comprise a polymerization product of at least a functional monomer and a low value r.sub.2/r.sub.s monomer. The ion exchange membranes may have an apparent permselectivity of at least about 95% and a resistivity of less than about 1.5 Ohm-cm.sup.2.