(Invited) Anion Conducting Solid Polymer Ionomers Electrolytes for Fuel Cells and Electrolyzers

Abstract

Ion conducting polymer electrolytes provide an enabling technology for the creation of low temperature fuel cells, hydrogen producing water electrolyzers, and flow batteries. The critical parameters of solid polymer electrolytes include ionic conductivity, ion selectivity, chemical resistance and dimensional stability in the presence of excess water. High pH operation using anion conductive polymer electrolytes has several potential advantages over acid-based polymer devices including low-cost catalysts, hydrocarbon (non-perfluorinated) polymer, and low cost cell components. However, the identification and synthesis of stable, hydroxide conducting solid polymer electrolytes has been elusive.In this study, a family of hydroxide conducting, poly(norbornene) solid polymer electrolytes were synthesized and used in high-performance, durable membrane electrode assemblies for fuel cells and electrolyzers. In addition to membranes, covalently bonded, self-adherent, hydroxide conducting ionomers were used to form high-performance, durable membrane electrode assembly for water electrolysis. Electrodes made by grind-spray method were compared to electrodes prepared by the solvent-cast method. The self-adhesive ionomers and membranes are based on hydroxide conducting poly(norbornene) polymers. The effect of porous transport layer material and porosity was examined. High performance electrolysis with very low degradation rates was achieved using stainless steel and nickel porous transport layers.