Fuel cells are pollution free, and silent. An electrolyte is a chemical that can conduct electricity, and is at the heart of the fuel cell. Polymer electrolytes must be humidified in order for the fuel cell to function, can only operate over a limited temperature range, and are permeable. As a consequence, polymer electrolyte fuel cell systems require many auxiliary components and are less efficient than other types of fuel cells. Solid acids can conduct electricity at similar values to polymers, they don't need to be hydrated, and they can function at high temperatures, up to 250 degrees Centigrade.
Solid acids are also typically inexpensive compounds that are easy to manufacture.
But until now such solid acids have not been examined as fuel-cell electrolytes because they dissolve in water and can lose their shape at even slightly elevated temperatures. To solve these problems, Haile and her graduate students Dane Boysen, Calum Chisholm and Ryan Merle, operated the fuel cell at a temperature above the boiling point of water, and used a solid acid, CsHSO4, that is not very prone to shape changes. The next challenge, says Haile, is to reduce the electrolyte thickness, improve the catalyst performance, and, most importantly, prevent the reactions that can occur upon prolonged exposure to hydrogen. Still, she says, solid acid fuel cells are a promising development. While there is a great deal of development work that needs to be done before solid acid based fuel cells can be commercially viable, the potential payoff is enormous.