Adv. Mater. http://doi.org/p83 (2013)

Although proton exchange membrane (PEM) fuel cells are widely considered as technologically promising for next-generation electrical vehicles, they operate in a limited temperature range (typically around 60–80 °C), which requires expensive platinum catalysts. Using low-cost oxide-based catalysts would be practically advantageous for applications but this would involve designing PEM fuel cells that could function above 100 °C under low-humidity conditions. Meilin Liu and colleagues now report a family of tetrazole-based polymer electrolyte membranes that exhibit high proton conductivity over the temperature range 20–120 °C in low humidity. The PEMs are also stable over a wide potential range and exhibit electrochemical stability under harsh fuel-cell operating conditions. The authors believe that this class of membranes could simplify fuel-cell systems and lead to the development of fuel cells for zero-emission vehicles. They could also be suitable for small microelectronics devices that require fuel cells to be operable over a wide temperature range without bulky and complicated thermal-and water-management systems.