A composite high-temperature proton exchange membrane for a fuel cell is prepared using materials include PBI and composite A@B and phosphoric acid. A is nanoparticles with a free radical quenching function and B is C.sub.3N.sub.4 having a nanosheet structure. The mass fraction of composite A@B is 0.05-2 wt. % and the mass ratio of A to B in A@B is 1:1-1:20. Composite A@B is firstly prepared, and A@B is then ultrasonically dispersed with a strong polar aprotic solvent to obtain a dispersion S1. PBI solution S2 is obtained from PBI and a strong polar aprotic solvent. S1 and S2 are uniformly mixed and stirred to obtain a casting solution S3, which is cast on plate glass with a groove. The membrane is then soaked in phosphoric acid after dying to obtain a composite membrane for a high-temperature proton fuel cell.

A preparation process of composite membrane for fuel cells uses an expanded polytetrafluoroethylene microporous base membrane as a skeleton. The base membrane is subjected to an impregnation treatment of mixed solutions having different concentrations from low to high. Specifically, the treatment tank I is provide with a mixed solution of a 0.1 wt. %-1 wt. % perfluorosulfonic acid resin solution, a water-retaining agent and a free radical quencher, the treatment tank II is provided with a mixed solution of a 2 wt. %-6 wt. % perfluorosulfonic acid resin solution, a water-retaining agent and a free radical quencher, and the treatment tank III is provided with a mixed solution of a 7 wt. %-20 wt. % perfluorosulfonic acid resin solution and a sulfonated polyetheretherketone solution. The resulting proton exchange composite membrane does not generate pore residues and avoids hydrogen permeation when in use.

A preparation process of composite membrane for fuel cells uses an expanded polytetrafluoroethylene microporous base membrane as a skeleton. The base membrane is subjected to an impregnation treatment of mixed solutions having different concentrations from low to high. Specifically, the treatment tank I is provide with a mixed solution of a 0.1 wt. %-1 wt. % perfluorosulfonic acid resin solution, a water-retaining agent and a free radical quencher, the treatment tank II is provided with a mixed solution of a 2 wt. %-6 wt. % perfluorosulfonic acid resin solution, a water-retaining agent and a free radical quencher, and the treatment tank III is provided with a mixed solution of a 7 wt. %-20 wt. % perfluorosulfonic acid resin solution and a sulfonated polyetheretherketone solution. The resulting proton exchange composite membrane does not generate pore residues and avoids hydrogen permeation when in use.

A flow battery having at least one rechargeable cell is disclosed. The at least one rechargeable cell can include an anolyte compartment, a catholyte compartment, and an anion exchange membrane positioned between the anolyte and catholyte compartments. The anion exchange membrane can have a thickness of less than 100 m and a steady state diffusivity of less than 0.4 ppm/hr/cm.sup.2 with respect to a cation species in an electrolyte of the rechargeable cell. A method of facilitating use of a flow battery including providing the anion exchange membrane is also disclosed. A method of facilitating storage of an electric charge comprising providing the flow battery is also disclosed. A method of producing an anion exchange membrane is also disclosed.

To provide a method for producing a fluorinated polymer, in which it is possible to efficiently and easily control the molecular weight to be proper when polymerizing a perfluoromonomer having a dioxolane ring containing a polymerizable double bond in the ring skeleton, and in which the obtainable fluorinated polymer is less susceptible to a decrease in molecular weight even when contacted with a base. A method for producing a fluorinated polymer, comprising polymerizing a raw-material mixture which contains at least one of a monomer composition M11 which comprises a perfluoromonomer represented by the formula m11 and a fluorinated monomer m11H having at least some of fluorine atoms of said perfluoromonomer substituted by hydrogen atoms, and a monomer composition M12 which comprises a perfluoromonomer represented by formula m12 and a fluorinated monomer m12H having at least some of fluorine atoms of said perfluoromonomer substituted by hydrogen atoms, wherein the total amount of the fluorinated monomer mil H and the fluorinated monomer m12H is from 10 to 1,100 ppm to the total amount of the monomer composition M11 and the monomer composition M12. ##STR00001##

To provide a method for producing a fluorinated polymer, in which it is possible to efficiently and easily control the molecular weight to be proper when polymerizing a perfluoromonomer having a dioxolane ring containing a polymerizable double bond in the ring skeleton, and in which the obtainable fluorinated polymer is less susceptible to a decrease in molecular weight even when contacted with a base. A method for producing a fluorinated polymer, comprising polymerizing a raw-material mixture which contains at least one of a monomer composition M11 which comprises a perfluoromonomer represented by the formula m11 and a fluorinated monomer m11H having at least some of fluorine atoms of said perfluoromonomer substituted by hydrogen atoms, and a monomer composition M12 which comprises a perfluoromonomer represented by formula m12 and a fluorinated monomer m12H having at least some of fluorine atoms of said perfluoromonomer substituted by hydrogen atoms, wherein the total amount of the fluorinated monomer mil H and the fluorinated monomer m12H is from 10 to 1,100 ppm to the total amount of the monomer composition M11 and the monomer composition M12. ##STR00001##

The electrochemical energy conversion system include an anode, a cathode, and a proton exchange membrane disposed between the anode and the cathode. The proton exchange membrane includes a polymer having a hard block polymer, a soft block polymer, and one or more hydrophilic functional groups attached to the soft block polymer. The glass transition temperature of the hard block polymer is higher than a glass transition temperature of the soft block polymer, such that the hard block polymer is non-elastic and the soft block polymer is elastic at a desired operating temperature. The hydrophilic functional groups are attached to the soft block polymer via a thiol-ene reaction to modify double bonds in the soft block polymer. The swellable functional groups are selectively connected to the soft domains of the block copolymers, so that when the membrane swells (under hydration or gas adsorption), the stress is effectively absorbed by the soft domain and the impact on overall mechanical properties is minor, resulting in more durable membranes.

The electrochemical energy conversion system include an anode, a cathode, and a proton exchange membrane disposed between the anode and the cathode. The proton exchange membrane includes a polymer having a hard block polymer, a soft block polymer, and one or more hydrophilic functional groups attached to the soft block polymer. The glass transition temperature of the hard block polymer is higher than a glass transition temperature of the soft block polymer, such that the hard block polymer is non-elastic and the soft block polymer is elastic at a desired operating temperature. The hydrophilic functional groups are attached to the soft block polymer via a thiol-ene reaction to modify double bonds in the soft block polymer. The swellable functional groups are selectively connected to the soft domains of the block copolymers, so that when the membrane swells (under hydration or gas adsorption), the stress is effectively absorbed by the soft domain and the impact on overall mechanical properties is minor, resulting in more durable membranes.

Described herein are stable hydroxide ion-exchange polymers and devices including the stable hydroxide ion-exchange N polymers. The polymers include ionenes, which are polymers that contain ionic amines in the backbone. The polymers are alcohol-soluble and water-insoluble. The polymers have a water uptake and an ionic conductivity that are correlated to a degree of N-substitution. Methods of forming the polymers and membranes including the polymers are also provided. The polymers are suitable, for example, for use as ionomers in catalyst layers for fuel cells and electrolyzers.

Described herein are stable hydroxide ion-exchange polymers and devices including the stable hydroxide ion-exchange N polymers. The polymers include ionenes, which are polymers that contain ionic amines in the backbone. The polymers are alcohol-soluble and water-insoluble. The polymers have a water uptake and an ionic conductivity that are correlated to a degree of N-substitution. Methods of forming the polymers and membranes including the polymers are also provided. The polymers are suitable, for example, for use as ionomers in catalyst layers for fuel cells and electrolyzers.