Promising to provide fuel cells up to 90% smaller, lighter, and less expensive than current devices, compact mixed-reactant (CMR) technology from energy systems developer CMR Fuel Cells (Cambridge, U.K.) uses mixed reactants and hydrodynamic flow through porous cell structures to significantly reduce fuel-cell material requirements.

Lighter and less-expensive fuel cells will enable the creation of battery-free portable electronic devices with little or no compromise in packaging and cost.

In contrast to traditional fuel-cell designs where the electrolyte membrane acts as a physical barrier between the fuel and the oxygen supplied to the cathode, a CMR-based fuel cell uses highly selective electrocatalysts to replace the conventional platinum catalyst and enable the fuel and oxidant streams to be mixed together.

By passing this fluid mixture through a porous or perforated tight membrane electrode assembly, the bipolar flow-field plates can be eliminated and much thinner and cheaper electrolyte materials used.

Because there is no need for physical separation of fuel and oxidant, crossover and pin-holing issues are rendered irrelevant and impermeable membranes, separators, and seals are no longer required. In the future, it may be possible to develop CMR technology for solid oxide and hydrogen-fuelled polymer electrolyte membrane fuel cells.

The company is currently executing a laboratory-based development program leading to a first demonstration of a CMR direct-methanol fuel-cell stack in July 2005.

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