Methods to Advance Technology of Proton Exchange Membrane Fuel Cells

Abstract

Proton exchange membrane (PEM) fuel cells showing promise of a high level of performance have, up to the present time, used electrodes containing a high platinum loading (4 mg/cm 2 ). We report improvements in performance of PEM fuel cells utilizing electrodes with only one‐tenth of this platinum loading by ( i ) extension of the three‐dimensional reaction zone by incorporation of a proton conductor (Nafion) into the electrode structure; ( ii ) optimization of the amount of Nafion impregnated into the electrode structure; ( iii ) hot‐pressing the impregnated electrodes to the Nafion membrane at 120°C and 50 atm; ( iv ) optimal humidification of reactant gases at a temperature above that of the cell (5°C for or air and 10°–15°C for ); and ( v ) operation at elevated temperatures and pressures. The performance of the cells was analyzed from measurements of cell potential vs. current density and of cell potential at constant current density vs. time. Cyclic voltammetry proved to be a useful tool to ascertain the electrochemically active area of the electrodes.