An efficient proton conducting electrolyte membrane for high temperature fuel cell in aqueous-free medium

A novel composite membrane, derived from a simple combination of a phosphate based alkylimidazolium ionic liquid used as an anhydrous proton conductor in sulfonated poly (ether ether ketone) polymer matrix, was first proposed and characterized. Observed thermal, mechanical and chemical stabilities of ionic liquid doped composite membranes were finest to use in fuel cell applications. The effective anhydrous proton conductivity with respect to various ionic liquid compositions was studied as a function of different temperatures. Under anhydrous environment the composite membranes were found to have a comparatively good conductivity in the range of 1.25–3.16 mS cm–1 at 145 °C as measured by impedance analyzer. Fuel cell performance with SPEEK/50% IL doped composite membrane gave a maximum power density of 203 mW/cm2 at 145 °C. This study foresees that the new composite membranes could be a promising water-free anhydrous proton transport membrane for fuel cells.