An operationally flexible fuel cell based on quaternary ammonium-biphosphate ion pairs

Fuel cells are promising devices for clean power generation in a variety of economically and environmentally significant applications. Low-temperature proton exchange membrane (PEM) fuel cells utilizing Nafion require a high level of hydration, which limits the operating temperature to less than 100 degrees C. In contrast, high-temperature PEM fuel cells utilizing phosphoric acid-doped polybenzimidazole can operate effectively up to 180 degrees C;however, these devices degrade when exposed to water below 140 degrees C. Here we present a different class of PEM fuel cells based on quaternary ammonium-biphosphate ion pairs that can operate under conditions unattainable with existing fuel cell technologies. These fuel cells exhibit stable performance at 80-160 degrees C with a conductivity decay rate more than three orders of magnitude lower than that of a commercial hightemperature PEM fuel cell. By increasing the operational flexibility, this class of fuel cell can simplify the requirements for heat and water management, and potentially reduce the costs associated with the existing fully functional fuel cell systems.