A fuel cell membrane electrode assembly including a polymer electrolyte membrane (PEM) and first and second electrodes. The PEM is situated between the first and second electrodes. The first electrode includes a first catalyst material layer including a first catalyst material and having first and second surfaces. The first electrode includes first and second material layers adjacent to the first and second surfaces, respectively, of the first catalyst material. The first material layer faces away from the PEM and the second material layer faces the PEM. The first material layer comprises a graphene-based material layer having a number of defects configured to mitigate dissolution of the first catalyst material through the first material layer.

A fuel cell membrane electrode assembly including a polymer electrolyte membrane (PEM) and first and second electrodes. The PEM is situated between the first and second electrodes. The first electrode includes a first catalyst material layer including a first catalyst material and having first and second surfaces. The first electrode includes first and second material layers adjacent to the first and second surfaces, respectively, of the first catalyst material. The first material layer faces away from the PEM and the second material layer faces the PEM. The first material layer comprises a graphene-based material layer having a number of defects configured to mitigate dissolution of the first catalyst material through the first material layer.

A composite polymer electrolyte membrane comprising a nanofiber sheet having a basis weight of 1.5 g/m.sup.2 or more and 4.0 g/m.sup.2 or less, and a proton-conducting polymer, the electrolyte membrane having a sheet shape in which the proton-conducting polymer and the nanofiber sheet are combined, and having an average coefficient of linear expansion of 300 ppm/K or less from 20° C. to 120° C. in an in-plane direction of the sheet shape.

A composite polymer electrolyte membrane comprising a nanofiber sheet having a basis weight of 1.5 g/m.sup.2 or more and 4.0 g/m.sup.2 or less, and a proton-conducting polymer, the electrolyte membrane having a sheet shape in which the proton-conducting polymer and the nanofiber sheet are combined, and having an average coefficient of linear expansion of 300 ppm/K or less from 20° C. to 120° C. in an in-plane direction of the sheet shape.

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.

A membrane electrode assembly includes: an electrolyte membrane; a cathode and an anode, each being stacked on the electrolyte membrane; and subgaskets bonded to a peripheral region of the electrolyte membrane, which is outside an active area, in which each of the cathode and the anode are stacked on the electrolyte membrane. The electrolyte membrane is disposed in at least a portion of the peripheral region of the electrolyte membrane, which is outside the active area, with a water discharge blocking region for preventing water in the electrolyte membrane from diffusing and being discharged to outside.

A membrane electrode assembly includes: an electrolyte membrane; a cathode and an anode, each being stacked on the electrolyte membrane; and subgaskets bonded to a peripheral region of the electrolyte membrane, which is outside an active area, in which each of the cathode and the anode are stacked on the electrolyte membrane. The electrolyte membrane is disposed in at least a portion of the peripheral region of the electrolyte membrane, which is outside the active area, with a water discharge blocking region for preventing water in the electrolyte membrane from diffusing and being discharged to outside.

A polymer electrolyte membrane, a method for manufacturing the same, and a membrane electrode assembly containing the polymer electrolyte membrane are disclsosed. The polymer electrolyte membrane includes: a fluorine-based support containing a plurality of pores due to polymer microfibrillar structures; a hybrid porous support placed on one side or both surfaces of the fluorine-based support and comprising nanowebs obtained by integrating nanofibers into a nonwoven fabric containing a plurality of pores; and ion conductors with which the pores of the porous support are filled. The polymer electrolyte membrane can reduce hydrogen permeability while being excellent in both durability and ion conductivity.

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 core-shell particle with a ceramic core and a hydrogel shell provided on a surface of the ceramic core, wherein the hydrogel shell is formed through polymerizing a monomer comprising a first compound having an ethylenically unsaturated group and a functional group capable of forming hydrogen bonds with water and a second compound having two or more ethylenically unsaturated groups and an inorganic element, a polymer electrolyte membrane including the core-shell particle, a fuel cell or an electrochemical cell including the polymer electrolyte membrane, and a method for preparing a core-shell particle.