A novel, easily synthesized, anhydrous derivative of phosphoric acid for use in electrolyte with phosphoric acid-based fuel cells

We build on the success of phosphoric acid as a fuel cell electrolyte, by designing a variant of the molecular acid that provides increased temperature range without sacrifice of high temperature conductivity or open circuit voltage. This is achieved by introduction of a hybrid component, based on silicon coordination of phosphate groups, which prevents decomposition or water loss to 250 °C, while enhancing free proton motion. We report conductivity studies to 285 °C and full H₂/O₂cell polarization curves to 226 °C with careful monitoring of fuel consumption. The current efficiency we report (current density per unit of fuel supplied per sec) is as high as the highest on record. A power density of 184 mW cm^-2 is achieved at 226 °C with hydrogen flow rate of 4.1 ml min^-1.