Fuel cells, a promising form of alternative energy, on a most basic level consists of a reaction between hydrogen and another chemical, which can be used to drive electrical current.  Typically, the other chemical is oxygen, which is advantageous in that the byproduct is clean water.  The key element to this process working efficiently is keeping the chemicals in a constant state of proper limited exposure, and often to catalyze the reaction.  To do this, special membranes go between the two gas fuel components.

Fuel cells are advantageous in that they can run for long periods of time and do not require combustion, producing less waste heat.  Their lack of moving parts, in most designs, is another advantage.  These pluses have led to their adoption for use in submarines, remote weather stations, satellites, and other remote applications.

Now researchers at Duke University's Pratt School of Engineering developed a breakthrough in membrane technology.  The researchers created a membrane with the key component being iron nanoparticles.  This special new membrane promises higher efficiency.  Furthermore, it should allow fuel cells to operate at lower humidity and, theoretically, at higher temperatures with less degradation.  

The research is being reported in the Journal of Membrane Science.

Mark Wiesner, Ph.D., a Duke civil engineer and senior author of the paper, explains the new membrane's advantages, stating, "The current gold standard membrane is a polymer that needs to be in a humid environment in order to function efficiently.  If the polymer membrane dries out, its efficiency drops. We developed a ceramic membrane made of iron nanoparticles that works at much lower humidity. And because it is a ceramic, it should also tolerate higher temperatures.  If the next series of tests proves that fuel cells with these new membranes perform well at high temperatures, we believe it might attract the type of investment needed to bring this technology to the market."

The current most commonly used membrane, Nafion, was first developed in the 1960s and has changed relatively little since.  This polymeric membrane becomes unstable at high temperatures and loses efficiency due to dehydration.  Nafion membranes are pricey, accounting for nearly 40 percent of the cost of the average system by Wiesner's estimates.  Wiesner's membranes are significantly cheaper to manufacture.

The key to proving his new membrane's value are high-temperature trials, says Wiesner.  Wiesner states, "The efficiency of current membranes drops significantly at temperatures over 190 degrees Fahrenheit.  However, the chemical reactions that create the electricity are more efficient at high temperatures, so it would be a big improvement for fuel cell technology to make this advance."

Wiesner and his team aren't done yet, however.  The extremely pure water produced from the reactions is no longer needed to humidify the cell, thus it can be removed and used for other purposes. Wiesner and his team are also tinkering with the membrane's fabrication to try to make it more flexible and more durable.