INTERNAL HYDRATION H-2/O-2 100 CM(2) POLYMER ELECTROLYTE MEMBRANE FUEL-CELL

This work deals with a new arrangement of a polymer electrolyte membrane fuel cell (PEMFC) support which allows the operation of a 100 cm(2) surface area fuel cell with cold and unhumidified gases. Hydrogen is not recycled. Both gases(pure hydrogen and oxygen) are heated and humidified internally, each one crossing a porous carbon block. This allows a simplified water management. Classical low platinum loading E-Tek(R) electrodes, hot-pressed on Nafion(R) 117 and 112 membranes, are used. Performances are then a little higher than those of comparable PEMFCs in the literature: 0.7 V at 0.7 A/cm(2) for Nafion(R) 117, and 0.724 V at 1 A/cm(2) for Nafion(R) 112, under 4/6 bar (absolute) of H-2/O-2 at 100 degrees C. The values of PEMFC resistance obtained in fitting the data were found to be R=0.254 (with Nafion(R) 117) acid 0.108 n cm(2) (with Nafiona(R) 112). The membrane contribution to the cell resistance was then estimated to be R(m)= 0.204 and 0.058 Omega cm(2), respectively (with Nafion(R) conductivity estimated at 0.103 S/cm at 100 degrees C in working fuel cell conditions). This membrane is therefore the major contributor to the total cell resistance.