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##

An electrolyte membrane is described that has improved bondability with a catalyst layer and that achieves good power generation performance, without the electrolyte membrane undergoing a physical treatment and without any loss of surface modification effect, where the electrolyte membrane comprises a polymer electrolyte and a nonionic fluorochemical surfactant.

An electrolyte membrane is described that has improved bondability with a catalyst layer and that achieves good power generation performance, without the electrolyte membrane undergoing a physical treatment and without any loss of surface modification effect, where the electrolyte membrane comprises a polymer electrolyte and a nonionic fluorochemical surfactant.

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.

Provided are an proton conducting polymer electrolyte membrane and a manufacturing method thereof which control the proton conducting nanochannel size and proton conductivity by phase separation improvement of a polar aprotic solvent in casting the proton conducting polymer electrolyte membrane.

Provided are an proton conducting polymer electrolyte membrane and a manufacturing method thereof which control the proton conducting nanochannel size and proton conductivity by phase separation improvement of a polar aprotic solvent in casting the proton conducting polymer electrolyte membrane.

A membrane for fuel cells, such as PEM and/or AEM fuel cells and/or electrolyzers is disclosed. Such a membrane (e.g., an anion conducting membrane) may include: crosslinked ionomer comprising two types of functional groups: a first type of functional groups forming crosslinking bonds between two ionomer chains; and a second type of functional groups comprising ion conducting functional groups. In some embodiments, the crosslinking bonds may not include the ion conducting functional groups. A catalyst coated membrane (CCM) is also disclosed. In such case the membrane may further include at least one catalyst layer attached to at least one side of the membrane to form the catalyst coated membrane (CCM). The at least one catalyst layer may include catalyst nanoparticles and crosslinked ionomer of the catalyst layer comprising two types of functional groups.

A membrane for fuel cells, such as PEM and/or AEM fuel cells and/or electrolyzers is disclosed. Such a membrane (e.g., an anion conducting membrane) may include: crosslinked ionomer comprising two types of functional groups: a first type of functional groups forming crosslinking bonds between two ionomer chains; and a second type of functional groups comprising ion conducting functional groups. In some embodiments, the crosslinking bonds may not include the ion conducting functional groups. A catalyst coated membrane (CCM) is also disclosed. In such case the membrane may further include at least one catalyst layer attached to at least one side of the membrane to form the catalyst coated membrane (CCM). The at least one catalyst layer may include catalyst nanoparticles and crosslinked ionomer of the catalyst layer comprising two types of functional groups.

A reinforced ion-conducting membrane comprises a planar reinforcing component which comprises a porous polymer material; an ion-conducting component embedded in at least a region of the planar reinforcing component, which ion-conducting component comprises an ion-conducting polymer material; and linking groups which are chemically bonded to both the planar reinforcing component and the ion-conducting component. The reinforced ion-conducting membrane is useful as the membrane in a membrane-electrode assembly for example as used in fuel cells.

A reinforced ion-conducting membrane comprises a planar reinforcing component which comprises a porous polymer material; an ion-conducting component embedded in at least a region of the planar reinforcing component, which ion-conducting component comprises an ion-conducting polymer material; and linking groups which are chemically bonded to both the planar reinforcing component and the ion-conducting component. The reinforced ion-conducting membrane is useful as the membrane in a membrane-electrode assembly for example as used in fuel cells.