Proton-exchange membranes for hydrogen-air fuel cells

The review is devoted to recent advances in the development of polymer electrolytes for low-temperature (operating temperatures ∼80°C) and medium-temperature (operating temperatures 160–180°C) fuel cells. At present the most used are perfluorinated polymer membranes, such as Nafion®, Aciplex®, Flemon®, and Dow®, owing to their high chemical stability and proton conductance, as well as good machinability. However, successful commercialization of fuel cells with such membranes is prevented by their high cost, as well as low proton conductance at low humidities and temperatures above 100°C. Much effort is underway to develop membranes alternative to perfluorinated ones, with emphasis on aromatic hydrocarbon polymers.