Stabilizing the imidazolium cation in hydroxide-exchange membranes for fuel cells.

Stable and able: The hydroxide-conducting cationic functional group used in the hydroxide-exchange membranes of fuel cells is key to controlling chemical stability and solubility. A new imidazolium cation, 1,4,5-trimethyl-2-(2,4,6-trimethoxyphenyl)imidazolium, is designed to take advantage of both strong electron-donation properties and steric hindrance. Synergy between these two effects leads to an efficient hydroxide-exchange membrane, with increased alkaline stability and improved OH(-) conductivity.