The present invention relates to a composition for fuel cell membranes and a process for the preparation thereof. In particular, the present invention relates to thermo-mechanically and chemically stable polymer electrolyte membranes which have been prepared without compromising proton conductivity by using multifunctional polydopamine and mechanically robust nanocellulose.

A process for the recovery of a perfluorosulphonic acid ionomer from a component comprising a perfluorosulphonic acid ionomer is disclosed, the process comprising immersing the component comprising the perfluorosulphonic acid ionomer in a solvent comprising an aliphatic diol and heating. Also disclosed is the use of the recovered perfluorosulphonic acid ionomer, for example in to prepared a proton conducting membrane or a catalyst ink.

To provide an ion exchange membrane for alkali chloride electrolysis for which membrane strength is increased while membrane resistance is reduced to reduce electrolysis voltage during alkali chloride electrolysis and which prevents peeling between layers (S) and a layer (C). The ion exchange membrane for alkali chloride electrolysis comprises a layer (C) which comprises a fluorinated polymer having carboxylic acid functional groups, at least two layers (S) which comprise a fluorinated polymer having sulfonic acid functional groups, and a reinforcing material, wherein the layers (S) include a layer (Sa) and a layer (Sb), the layer (Sa) is a layer which is adjacent to the layer (C), the layer (Sb) is a layer which is not adjacent to the layer (C), the reinforcing material is disposed in the layer (Sb) substantially in parallel to the layer (Sb) in a state not in contact with the layer (Sa), and the ion exchange capacity of the layer (Sa) is lower than the ion exchange capacity of the layer (Sb).

The present invention pertains to a process for manufacturing a film, said process comprising: (i) providing a composition [composition (C)] comprising, preferably consisting of: —at least one fluoropolymer [polymer (F)] comprising recurring units derived from at least one fluorinated monomer comprising a —SO 3 M functional group, wherein M is an alkaline metal [monomer (FM)] and—a liquid medium [medium (L)] comprising at least 50% by weight, based on the total weight of said medium (L), of at least one alkyl carbonate; (ii) processing the composition (C) provided in step (i) into a film; and (iii) drying the film provided in step (ii). The present invention further pertains to use of said film in a process for manufacturing a lithium electrode and to use of said lithium electrode in a process for manufacturing a lithium-sulphur battery.

The present invention provides an electrolyte membrane for a redox flow battery, comprising a perfluorocarbon polymer having an ion-exchange group, wherein the perfluorocarbon polymer has equivalent weight EW of the ion-exchange group of 600 g/eq or more and 2000 g/eq or less, a craze area ratio of the electrolyte membrane is 1.5% or less, and a relative dimension of the electrolyte membrane in at least one of a X direction and a Y direction is 80% or more and less than 100% in the following relative dimension by dipping in 2 M aqueous sulfuric acid solution.

Provided is a polymer electrolyte membrane comprising: (a) a polyelectrolyte having an ion exchange capacity of from 0.5 to 3.0 meq/g; and (b) at least one scandium compound selected from the group consisting of scandium oxide, scandium acetate, scandium sulfate, scandium nitrate, and scandium carbonate, wherein a polyethylene glycol (PEG)-derived compound in the polymer electrolyte membrane has a total content of 10 ppm or less.

[Problem to be Solved]

Provided are an aqueous dispersion of a fluoroolefin and the like that do not corrode vessels and enable a copolymer to be given at a high conversion ratio and high productivity from the fluoroolefin as a raw material monomer.

[Solution]

An aqueous dispersion containing: a fluoroolefin (a) represented by the following general formula (1); a surfactant (c) represented by the following general formula (2); and a dispersion medium containing water, wherein the aqueous dispersion has a cumulant diameter of 250 to 2,000 nm, and the aqueous dispersion has a pH of 2.0 to 7.0:

CF.sub.2═CF—[O—CF.sub.2—CF(CF.sub.3)].sub.n—O—[CF.sub.2].sub.m—Z   (1) wherein n represents an integer of 0 or more and 2 or less, m represents an integer of 2 or more and 4 or less, and Z represents CF.sub.3, SO.sub.2F, or COOH.sub.3, and

CF.sub.3—[CF.sub.2].sub.m—O—[CF(CF.sub.3)—CF.sub.2—O].sub.n—CF(CF.sub.3)—Z   (2) wherein m represents an integer of 0 to 2, n represents an integer of 0 to 6, Z represents COOM, wherein N represents H, Li, Na, K, or NR.sub.4, wherein R represents H or a linear alkyl group having 1 to 4 carbon atoms.

An ion exchange membrane has multiple layers of ionic polymers which each contain substantially different chemical compositions. i.e. varying side chain lengths, varying backbone chemistries or varying ionic functionality. Utilizing completely different chemistries has utility in many applications such as fuel cells where for example, one layer can help reduce fuel crossover through the membrane. Or one layer can impart substantial hydrophobicity to the electrode formulation. Or one layer can selectively diffuse a reactant while excluding others. Also, one chemistry may allow for impartation of significant mechanical properties or chemical resistance to another more ionically conductive ionomer. The ion exchange membrane may include at least two layers with substantially different chemical properties.

To provide a sulfonic acid group-containing polymer which is capable of forming a low hydrogen permeable membrane, which shows a high ion exchange capacity, and which shows a proper softening temperature. The sulfonic acid group-containing polymer has units u1 represented by the following formula u1, units u2 represented by the following formula u2, and units u3 based on tetrafluoroethylene,

##STR00001##

in the formula u1, R.sup.F1 and R.sup.F2 are each independently a C.sub.1-3 perfluoroalkylene group, and Z.sup.+ is a hydrogen ion, a metal ion, or an ammonium ion,

—[CF.sub.2—CF(CF.sub.2O—R.sup.f1)]—  Formula u2

in the formula u2, R.sup.f1 is a perfluoroalkyl group which may contain a SO.sub.3.sup.−Z.sup.+ group and/or an etheric oxygen atom.

A method for producing an electrolyte solution including a supply step of continuously supplying an emulsion based a polymer electrolyte and a solvent into a dissolution facility, and a dissolution step of continuously dissolving the polymer electrolyte in the solvent by heating the interior of the dissolution facility to obtain the electrolyte solution.