Protonated phosphonic acid electrodes for high power heavy-duty vehicle fuel cells

Abstract

High-temperature polymer electrolyte membrane fuel cells are promising for heavy-duty vehicle applications, but strides in performance are needed to improve their commercial viability. Here it is demonstrated that protonating phosphonic acid electrodes greatly enhances power density and durability.,State-of-the-art automotive fuel cells that operate at about 80 degrees C require large radiators and air intakes to avoid overheating. High-temperature fuel cells that operate above 100 degrees C under anhydrous conditions provide an ideal solution for heat rejection in heavy-duty vehicle applications. Here we report protonated phosphonic acid electrodes that remarkably improve the performance of high-temperature polymer electrolyte membrane fuel cells. The protonated phosphonic acids comprise tetrafluorostyrene-phosphonic acid and perfluorosulfonic acid polymers, where a perfluorosulfonic acid proton is transferred to the phosphonic acid to enhance the anhydrous proton conduction of fuel cell electrodes. By using this material in fuel cell electrodes, we obtained a fuel cell exhibiting a rated power density of 780 mW cm(-)(2) at 160 degrees C, with minimal degradation during 2,500 h of operation and 700 thermal cycles from 40 to 160 degrees C under load.,