Polybenzimidazole-based membranes are nowadays considered the best alternative to Nafion® for the fabrication of high-temperature polymer fuel cells. The rich chemistry of benzimidazole allows us to widely change the physicochemical properties of the resulting polymers and, consequently, to tune the functional properties of the electrolyte membrane. In this perspective we report the most recent developments in PBI-based membranes, cells and stacks. Emphasis is given to problems such as acid leaching, membrane degradation and stack durability.
