Abstract: Non-proton cationic impurities are removed from the ionomer in a proton exchange membrane of an electrochemical cell and from the anode side and cathode side catalyst layers. A supply path for an anode feed to the ionomer on the anode side of the proton exchange membrane and a supply path for a cathode feed to the ionomer on the cathode side of the proton exchange membrane are provided. A regenerating fluid with acidic pH is brought into contact with the ionomer on the cathode side of the proton exchange membrane to accomplish an ion exchange of the non-proton cationic impurities with protons and thus remove the non-proton cationic impurities from the ionomer into the regenerating fluid. This removes the non-proton cationic impurities from the ionomer of the electrochemical cell without increasing the risk of corrosion and without interrupting the process of the electrochemical cell.

Abstract: An electrolyte membrane and method for generating the membrane provide a resistance as low as possible to minimize ohmic losses. The membrane has a low permeability for redox-active species. If redox-active species still cross the membrane, this transport is balanced during charge and discharge preventing a net vanadium flux and associated capacity fading. The membrane is mechanically robust, chemically stable in electrolyte solution, and low cost. A family of ion exchange membranes including a bilayer architecture achieves these requirements. The bilayer membrane includes two polymers, i) a polymer including N-heterocycles with electron lone pairs acting as proton acceptor sites and ii) a mechanically robust polymer acting as a support, which can be a dense cation exchange membrane or porous support layer. This bilayer architecture permits a very thin polymer film on a supporting polymer to minimize ohmic resistance and tune electrolyte transport properties of the membrane.

Abstract: A membrane with high ion selectivity, balancing influence on vanadium transport in all-vanadium redox-flow environment, high physicochemical stability and potentially low cost is an amphoteric ion exchange membrane with defined ratio of anion and cation exchange capacity, in particular for redox flow batteries. The membrane includes a mechanically robust and chemically resistant base polymer film (matrix), ion exchange groups covalently bound to the polymer matrix, being a mixture of anion and cation exchange groups, a comonomer including two anion exchange groups per molecule to yield a ratio of anion exchange groups to cation exchange groups of 1.5-4 (50-300% excess of anion exchange groups over cation exchange groups) to balance transport of positively charged redox-active ions, a quaternary bonded alpha-C atom in comonomers to protect the resulting polymer sterically against chemical degradation. Optionally, additional functional constituents, such as crosslinkers and/or antioxidants are provided.

Abstract: A method of preparing an ionomer of an ion exchange membrane with a recombination catalyst to prevent gas crossover of species, such as hydrogen and/or oxygen, to anodic and cathodic cell compartments of an electrochemical cell. An ionomer of an ion exchange membrane is prepared with a recombination catalyst. The ionomer is a proton or anion exchange polymer and the recombination catalyst, selected from the precious metals group, is provided in ionic form in a liquid metal salt solution. The ion exchange membrane is immersed into the liquid metal salt solution to exchange ionic ionomer ports with the ionic form of the recombination catalyst. The membrane is then assembled in the electrochemical cell and the ionic form of the recombination catalyst is at least partly reduced to metallic form by forcing hydrogen to permeate through the ionomer of the ion exchange membrane.

Abstract: Non-proton cationic impurities are removed from the ionomer in a proton exchange membrane of an electrochemical cell and from the anode side and cathode side catalyst layers. A supply path for an anode feed to the ionomer on the anode side of the proton exchange membrane and a supply path for a cathode feed to the ionomer on the cathode side of the proton exchange membrane are provided. A regenerating fluid with acidic pH is brought into contact with the ionomer on the cathode side of the proton exchange membrane to accomplish an ion exchange of the non-proton cationic impurities with protons and thus remove the non-proton cationic impurities from the ionomer into the regenerating fluid. This removes the non-proton cationic impurities from the ionomer of the electrochemical cell without increasing the risk of corrosion and without interrupting the process of the electrochemical cell.

Abstract: A membrane with high ion selectivity, balancing influence on vanadium transport in all-vanadium redox-flow environment, high physicochemical stability and potentially low cost is an amphoteric ion exchange membrane with defined ratio of anion and cation exchange capacity, in particular for redox flow batteries. The membrane includes a mechanically robust and chemically resistant base polymer film (matrix), ion exchange groups covalently bound to the polymer matrix, being a mixture of anion and cation exchange groups, a comonomer including two anion exchange groups per molecule to yield a ratio of anion exchange groups to cation exchange groups of 1.5-4 (50-300% excess of anion exchange groups over cation exchange groups) to balance transport of positively charged redox-active ions, a quaternary bonded alpha-C atom in comonomers to protect the resulting polymer sterically against chemical degradation. Optionally, additional functional constituents, such as crosslinkers and/or antioxidants are provided.

Abstract: An electrolyte membrane and method for generating the membrane provide a resistance as low as possible to minimize ohmic losses. The membrane has a low permeability for redox-active species. If redox-active species still cross the membrane, this transport is balanced during charge and discharge preventing a net vanadium flux and associated capacity fading. The membrane is mechanically robust, chemically stable in electrolyte solution, and low cost. A family of ion exchange membranes including a bilayer architecture achieves these requirements. The bilayer membrane includes two polymers, i) a polymer including N-heterocycles with electron lone pairs acting as proton acceptor sites and ii) a mechanically robust polymer acting as a support, which can be a dense cation exchange membrane or porous support layer. This bilayer architecture permits a very thin polymer film on a supporting polymer to minimize ohmic resistance and tune electrolyte transport properties of the membrane.

Abstract: A method of manufacturing gas diffusion layers (GDL) with a defined pattern of hydrophobic and hydrophilic regions is used to produce electrically conductive porous materials with distributed wettability. The method includes a) Coating the external and internal surfaces of a porous base material made of carbon fiber or Titanium with Fluoroethylene-Propylene (FEP) and/or perfluoroalkoxy (PFA) and/or Ethylene-Tetrafluoroethylene (ETFE) or any other hydrophobic polymer; b) Exposing the coated material to irradiation through a blocking mask such that only parts of the coated porous material are exposed; and c) Immersing the previously exposed material in a monomer solution and heating to a temperature higher than 45° C., resulting in the graft co-polymerization of monomers on the FEP layer.

Abstract: A novel approach based on the increase of the intrinsic oxidative stability of uncrosslinked membranes is addressed. The co-grafting of styrene with methacrylonitrile (MAN), which possesses a protected ?-position and strong dipolar pendant nitrile group, onto 25 ?m ETFE base film is disclosed. Styrene/MAN co-grafted membranes were compared to styrene based membrane in durability tests in single H2/O2 fuel cells. The incorporation of MAN improves the chemical stability dramatically. The membrane preparation based on the copolymerization of styrene and MAN shows encouraging results and offers the opportunity of tuning the MAN and crosslinker content to enhance the oxidative stability of the resulting fuel cell membranes.

Abstract: A method for preparing a membrane to be assembled in a membrane, electrode assembly includes the step of swelling an ion-conducting membrane in a liquid containing at least one solvent or to an atmosphere containing the vapor phase of at least one solvent by controlling the content of the solvent in the ion-conducting membrane. A method for manufacturing a membrane electrode assembly using an ion conducting membrane includes the steps of: providing an ion-conducting membrane in a pre-swollen state; coating the ion-conducting membrane on both sides with an electrode layer to form a sandwich; and hot-pressing the sandwich to form an ion-conducting bonding of the layers of the sandwich. Furthermore, a membrane electrode assembly is disclosed including a hot pressed sandwich having an electrode layer, a ion-conducting membrane and again an electrode layer, thereby using the ion-conducting membrane in its pre-swollen status prior to the hot-pressing.

Abstract: A novel approach based on the increase of the intrinsic oxidative stability of uncrosslinked membranes is addressed. The co-grafting of styrene with methacrylonitrile (MAN), which possesses a protected ?-position and strong dipolar pendant nitrile group, onto 25 ?m ETFE base film is disclosed. Styrene/MAN co-grafted membranes were compared to styrene based membrane in durability tests in single H2/O2 fuel cells. The incorporation of MAN improves the chemical stability dramatically. The membrane preparation based on the copolymerization of styrene and MAN shows encouraging results and offers the opportunity of tuning the MAN and crosslinker content to enhance the oxidative stability of the resulting fuel cell membranes.

Abstract: A membrane electrode assembly includes a cathode layer, an anode layer, and a polymer electrolyte sandwiched between the cathode layer and the anode layer. The polymer electrolyte layer is a polymer film having a plurality of sections. The sections are radiation grafted and sulfonated, wherein the sections are separated from each other by separation bands. The separation bands are untreated sections of the polymer electrolyte layer.

Abstract: In a method for preparing a membrane to be assembled in a membrane electrode assembly, such as a polymer electrolyte membrane fuel cell, a base polymer film is irradiated with at least one of electromagnetic and particle radiation in order to form reactive centers within the polymer film. The irradiated film is exposed to a mixture of monomers amenable to radical polymerization to form a graft copolymer in the irradiated film. The mixture includes ?-methylstyrene and methacrylonitrile. The grafted film is sulfonated to introduce sulfonic acid sites providing ionic conductivity of the material.

Abstract: A method for preparing a membrane to be assembled in a membrane, electrode assembly includes the step of swelling an ion-conducting membrane in a liquid containing at least one solvent or to an atmosphere containing the vapor phase of at least one solvent by controlling the content of the solvent in the ion-conducting membrane. A method for manufacturing a membrane electrode assembly using an ion conducting membrane includes the steps of: providing an ion-conducting membrane in a pre-swollen state; coating the ion-conducting membrane on both sides with an electrode layer to form a sandwich; and hot-pressing the sandwich to form an ion-conducting bonding of the layers of the sandwich. Furthermore, a membrane electrode assembly is disclosed including a hot pressed sandwich having an electrode layer, a ion-conducting membrane and again an electrode layer, thereby using the ion-conducting membrane in its pre-swollen status prior to the hot-pressing.

Abstract: The present invention relates to a composite membrane comprising at least one ion-conducting polymer and a network of randomly orientated individual fibers, wherein there is a continuous region of the membrane at one or both of the membrane faces wherein the density of fibers is lower than the density of fibers in the membrane as a whole. The invention further relates to processes for manufacturing membranes according to the invention, and membrane electrode assemblies comprising membranes according to the invention.

Abstract: The present invention relates to a composite membrane comprising at least one ion-conducting polymer and a network of randomly orientated individual fibres, wherein there is a continuous region of the membrane at one or both of the membrane faces wherein the density of fibres is lower than the density of fibres in the membrane as a whole. The invention further relates to processes for manufacturing membranes according to the invention, and membrane electrode assemblies comprising membranes according to the invention.