ANODE WATER REMOVAL - A WATER MANAGEMENT AND DIAGNOSTIC-TECHNIQUE FORSOLID POLYMER FUEL-CELLS

A water management technique has been developed for solid polymer elec trolyte fuel cells which demonstrates both performance and diagnostic benefits. Through this technique a substantial proportion of the water in the cathode can be removed via the anode fuel stream. This is acco mplished by imparting a water concentration gradient through the polym er membrane, thereby increasing the back diffusion rate of water. A re duction in cathode overpotential is observed without noticeable increa se in membrane resistance. The technique can be used to remove mass tr ansport limitations at both high current densities and low oxidant sto ichiometries.