High-Performance Direct Methanol Fuel Cell with Bipolar Membrane Structure

Power demands of objective force warriors are rapidly growing, increasing the need for small, light, energy-dense power supplies. The burden of batteries an individual soldier transports must be reduced. High energy density fuel cell systems offer a promising alternative to batteries with methanol being the most portable, convenient fuel. Conventional direct methanol fuel cells (DMFC’s) based on proton exchange membranes suffer from fuel stripping and crossover combustion losses. Most use dilute fuel, significantly reducing the system energy density. Direct methanol hydroxyl exchange membrane fuel cells (HEMDMFC) suffer from carbonate build up in the electrolyte at the catalyst interface, causing quick deterioration of performance. However, the HEMDMFC cathode allows the use of non-platinum oxygen reduction catalysts that are not active to methanol oxidation. The acid anode of the conventional PEMDMFC provides the benefit of discharging the oxidized carbon as gaseous carbon dioxide. Lynntech will develop a small, rugged system that maximizes utilization of the energy available in concentrated methanol through the use of a bipolar or double-bipolar membrane structure, taking advantage of both PEM and HEM fuel cell technologies. A single, low-power DC fan (the only peripheral for the system) will move air across the cathode, minimizing parasitic losses.