research & development
New Material Improves DMFC Power Output 50%
A team of MIT engineers led by Paula T. Hammond, Bayer Professor of Chemical Engineering, have created a material that improves the power output of a direct methanol fuel cell (DMFC) by more than 50%. The new material is also considerably less expensive than its conventional industry counterpart.
The MIT team focused on DMFCs in which the methanol is directly used as the fuel and reforming of alcohol down to hydrogen is not required. The material currently used for the electrolyte sandwiched between the electrodes of a DMFC is expensive. That material, known as Nafion, is permeable to methanol, allowing some of the fuel to seep across the center of the fuel cell. This wastes fuel and lowers the cell's efficiency because the fuel isn't available for the reactions that generate electricity.
Using a relatively new technique known as layer-by-layer assembly, the MIT researchers created an alternative to Nafion. "We were able to tune the structure of [our] film a few nanometers at a time, getting around some of the problems associated with other approaches," Hammond says. "The result is a thin film that is two orders of magnitude less permeable to methanol but compares favorably to Nafion in proton conductivity."
To test their creation, the engineers coated a Nafion membrane with the new film and incorporated it into a direct methanol fuel cell. The team is now exploring whether the new film could be used by itself, completely replacing Nafion. To that end, they have been generating thin films that stand alone, with a consistency much like plastic wrap.
This work was supported by the DuPont-MIT Alliance through 2007 and is currently supported by the National Science Foundation.
DLR Research Aircraft Takes Off Using Fuel Cell
The German Federal Ministry of Economics and Technology, through its aeronautics research program, Lufo IV, has commissioned the German Aerospace Center to develop fuel cells for a reliable on-board power supply for wide-body airliners.
The Antares DLR-H2 research aircraft, developed in cooperation with Lange Aviation GmbH and its propulsion system, are based on the Antares 20E self-launching motorglider, which has been in production for several years. Two additional external pods, housing the fuel cell system and the hydrogen tanks, are added underneath the wings, which have been strengthened for this purpose. In the future, the performance of the aircraft may be increased substantially by using up to four external pods, or by using fuel cells of an improved design. For the first time, DLR-H2 is able to take off using the energy from fuel cells.
Fuel cells are not expected to be usable as primary propulsive energy sources for passenger aircraft within the foreseeable future. The DLR's research is aimed at developing fuel cells under real operational conditions for use as reliable on-board power supplies in civil aviation.
