Abstract: Alkaline-stable cations were introduced to a polyolefin bearing phenyl side chains to enable manipulation of ion exchange capacity and hot pressing technique. Hydroxide exchange membranes or hydroxide exchange ionomers formed from these polymers exhibit superior chemical stability, hydroxide conductivity, decreased water uptake, good solubility in selected solvents, and improved device stability as compared to conventional hydroxide exchange membranes or ionomers. Hydroxide exchange membrane fuel cells and hydroxide exchange membrane electrolyzers comprising the polyolefin with pendant cation provide enhanced performance and durability at relatively high temperatures.

Abstract: Hydroxide-exchange membranes (HEMs) and hydroxide-exchange ionomers (HEIs) are provided which include polymers with oxidation resistant groups. The attachment of the oxidation resistant groups to the polymer backbone allows fine-tuning of the mechanical properties of the membrane and incorporation of alkaline stable cations, such as imidazoliums, phosphoniums and ammoniums, and provides enhanced stability to the polymer. HEMs/HEIs formed from these polymers exhibit superior chemical stability, anion conductivity, decreased water uptake, good solubility in selected solvents, and improved mechanical properties in an ambient dry state as compared to conventional HEM/HEIs. The HEMs exhibit enhanced stability in a highly oxidative environment.