Self-humidifying membrane and self-humidifying fuel cell

摘要

A self-humidifying fuel cell is made by preparing a porous substrate, coating the substrate with a zeolitic material and filling the pores with a proton-conducting material. The coating of the substrate includes selecting a zeolitic material, and applying coating on the pore walls and surface of the porous substrate, to form zeolitic material-coated pores. The resulting composite material is used as a self-humidifying proton-conducting membrane in a fuel cell.

主权项

1. A method of producing a self-humidifying membrane used in a self-humidifying fuel cell, the method comprising:
preparing a porous substrate with straight and tortuous pores having a pore size of 20 nanometers to 500 micrometers; coating the porous substrate with a continuous or non-continuous zeolitic material layer with a thickness of 0.1 to 100 micrometers selected from the group consisting of zeolites, molecular sieves and zeotypes to form zeolitic material-coated pore walls and surface, using a process selected at least one of the group consisting of direct synthesis, seeding and regrowth, surface grafting and dip-coating; filling the zeolitic material-coated pores with at least one proton-conducting material to form a structure for a self-humidifying membrane by impregnating the zeolitic material-coated pore walls and surface with a filling material containing the at least one proton-conducting material and solvents, vacuum drying sufficiently to remove the solvents, and repeating the impregnating and vacuum drying to completely fill the pores with the at least one proton-conducting material; and activating the structure, wherein the activating comprises removing solvents in the proton-conducting material precursors and porous structures of the zeolites, molecular sieves or zeotype materials to make the membrane self-humidifying, the zeolite, zeotype and/or molecular sieve regulates water within the self-humidifying membrane through adsorption of reaction generated water and/or catalytic formation of water, the filling the zeolitic material-coated pores with at least one proton-conducting material comprises preparing a subsequent precursor, said subsequent precursor comprising a sulfonated polymer precursor by use of a precursor having a solvent comprising at least one material selected from the group consisting of isopropanol, dimethyl sulfoxide, ethylene glycol, 1,2-propanediol and glycerol, followed by said vacuum drying, to form a confined proton-conducting polymer, the proton-conducting polymer confined within the coated pores in a configuration that limits shrinkage and swelling of the material caused by temperature changes and thermal effects, thereby improving mechanical and dimensional stabilities at high temperature, and the confinement induces rearrangement of the polymer chain and functional group conformation within the pores.