Sandia Develops PEM

A new type of polymer electrolyte membrane (PEM) is being developed by researchers at the Department of Energy’s Sandia National Laboratories to bring micro fuel cells closer to realization using diverse fuels like glucose, methanol, and hydrogen (See photo, page 1). The Sandia Polymer Electrolyte Alternative (SPEA) could provide new, uninterrupted autonomous power sources for sensors, communications, microelectronics, healthcare applications, and transportation.

Recently the membrane research team headed by Sandia researcher Chris Cornelius demonstrated that the new SPEA could operate as high as 140°C and produce a peak power of 1.1 watts per square centimeter at 2 amps per square centimeter at 80°C. Under identical operating conditions, the SPEA material can deliver higher power outputs with methanol and hydrogen than Nafion. Nafion is recognized as the newest PEM material for fuel cells.

Because the SPEA material can operate at elevated temperatures, it enables several key benefits that Nafion cannot provide. These advances include smaller fuel cell stacks because of better heat rejection, enhanced water management, and significant resistance to carbon monoxide poisoning. These performance properties suggest that the SPEA material may be a potential alternative to Nafion.

Cornelius notes that a higher temperature PEM material is one of the goals of the DOE’s Hydrogen, Fuel Cells, and Infrastructure Technologies Program. By 2005, one milestone is to develop polymer electrolyte membranes for automotive applications that operate at 120°C for 2,000 hours with low membrane interfacial resistance.

“We have already completed initial material validation studies of our SPEA with the help of our battery group and Los Alamos National Laboratory,” says Cornelius. “The next steps are to reduce the internal resistance in the fuel cell membrane electrode assembly, optimize catalyst and ionomer composition, improve the properties of the SPEA material, conduct life cycle testing in a fuel cell environment, and assess the potential value for large-scale commercialization of the polymer electrolyte.”