SIMULATION STUDIES ON THE FUEL ELECTRODE OF A H2-O2 POLYMER ELECTROLYTE FUEL-CELL

The macro-homogeneous porous electrode theory is used to develop a model which describes the catalyst layer of the hydrogen electrode formed by catalyst particles that are bonded to the membrane. The water transport in the catalyst layer and polymer electrolyte membrane is considered. The effects of catalyst layer structure parameters such as polymer volume fraction, catalyst layer thickness, platinum loading and reactant gas humidity as well as CO poison on the hydrogen electrode behavior are examined. The results show that the catalyst layer thickness has a significant effect on the electrode performance. A thicker catalyst layer will result in a larger ohmic voltage loss and higher catalyst cost. The optimal polymer volume fraction and catalyst layer thickness are 0.5 and 1.5-4 mum, respectively, for this electrode. An optimal platinum surface coverage on carbon need not exceed 20% (20 wt% Pt/C). Larger platinum coverage will increase the cost, out only slightly enhance the electrode performance.