Princeton Engineering

Fuel cell batteries might power clean cars of the future, but for now they are found in niche applications such as spacecraft, where cost is no object. “We are trying to figure out how you could build fuel cells that operate more simply and are cheaper to produce so that they would be acceptable in a consumer market,” said Princeton professor of chemical engineering Jay Benziger.

Fuel cells can be thought of as chemical reactors in which hydrogen and oxygen combine, generating electricity and water. Benziger works with polymer electrolyte membrane (PEM) fuel cells, which are said to hold the most promise for transport applications. To operate, PEM cells need water, which is provided by an auxiliary humidification system. In a landmark finding, Benziger has determined the optimum amount of water in the membrane that sustains the cell’s chemical reactions.

By understanding this and other key mechanisms of a fuel cell reactor, his research group has improved the system’s design. They have made a new reactor that eliminates the hardware and cost of humidification equipment. Instead, it uses the water produced by the fuel cell reaction itself. They are now developing new, less expensive polymer materials for the membranes. “There are still major obstacles to dramatically reduce cost and increase reliability that must be solved before fuel cells can compete with modern combustion engines,” Benziger said.