Direct Methanol Fuel Cells (DMFC)
For Small Portable Power Applications
The generation of portable power has been one of the persistent and vexing problems in electrochemistry. Conventional batteries can be fabricated to provide high power, but low specific energy can be a problem. Disposable and rechargeable batteries are substantial contributors of hazardous metals to landfills. Hydrogen-air fuel cells can provide good specific energy, but typically have only moderate power densities. However, in small portable power applications the direct methanol fuel cell (DMFC) is an excellent candidate, as one liter of methanol yields approximately 1 kW-hr of energy.
Unlike reformer-based systems which convert methanol to hydrogen (and CO and CO2) for subsequent oxidation in a hydrogen-air fuel cell, the DMFC directly oxidizes the methanol at the anode:
2 CH3OH + 2 H2O → 2 CO2 + 12 H+ + 12 e-
while reducing oxygen at the cathode:
3 O2 + 12 H+ + 12 e- → 6 H2O
So that the overall reaction is:
2 CH3OH + 3 O2 → 2 CO2 + 4 H2O
GES has performed extensive research and development of DMFCs, leading to the production of advanced prototypes for applications such as portable power for home and work use, light vehicle propulsion, and military systems.
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