"Our goal is to replace traditional fuel-cell membranes with these cost-effective, highly tunable and better-performing materials," Paula Hammond, Bayer Professor of chemical engineering and leader of the research team, said in a statement released Thursday (May 15).

Hammond's team focused on direct-methanol fuel cells (DMFCs), in which the methanol is used as the fuel, eliminating the need to distill alcohol to hydrogen as a fuel.

Current DMFCs have limitations. Nafion, the material currently used for the electrolyte sandwiched between the electrodes, is permeable to methanol, allowing seepage across the center of the fuel cell, thereby wasting fuel.

The MIT researchers created an alternative to Nafion using a layer-by-layer assembly technique. They were able to tune the structure of their film a few nanometers at a time. The resulting thin film is two orders of magnitude less permeable to methanol, but compares favorably to Nafion in proton conductivity, according to the researchers.

The researchers coated a Nafion membrane with the new film and incorporated it into a DMFC. The result was an increase in power output of more than 50 percent.

The team said it is now exploring whether the new film could be used to replace Nafion. To that end, they have been generating thin films that stand alone, with a consistency much like plastic wrap.

The team has also begun exploring the new material's use in photovoltaics as part of the MIT Energy Initiative.

The fuel cell research was supported by the DuPont-MIT Alliance. It is currently supported by the National Science Foundation.