US Patent 7799467 Solid polymer electrolytes from ethylene oxide-containing, layer-by-layer assembled films

A solid polymer electrolyte produced using a layer-by layer (LBL) assembly process. The solid electrolyte is assembled on a substrate by alternating exposure to dilute solutions of polycation and polyanion or hydrogen-bonding donor and hydrogen-bonding acceptor. Ethylene oxide content is introduced into the LBL film by 1) covalent grafting onto a polyionic species, 2) inclusion of an ethylene oxide (e.g. PEO) polymer as one of the two component species of a LBL assembly, or 3) the addition of ethylene oxide-containing small molecule, oligomer, or polymer to a fully assembled LBL polymer matrix. The prepared films were to be ultrathin SPE films with sound mechanical properties and ion conductivity to meet the needs of current applications, such as batteries, fuels cells, sensors and electrochromic devices.