Importance of Electrode Hot-Pressing Conditions for the Catalyst Performance of Proton Exchange Membrane Fuel Cells

The catalyst performance in a proton exchange membrane fuel cell (PEMFC) depends on not only the choice of materials, but also on the electrode structure and in particular on the interface between the components. In this work, we demonstrate that the hot-pressing conditions used during electrode lamination have a great influence on the catalyst properties of a low-temperature PEMFC, especially on its durability. Lamination pressure, temperature and duration were systematically studied in relation to the electrochemical surface area, platinum dissolution, platinum particle size and electrode surface composition. The degradation of the platinum catalyst and polymer was analyzed in relation to the preparation conditions. An optimal electrode interface structure can improve Pt performance by (1) providing high platinum utilization; (2) decreasing platinum migration and coalescence; (3) reducing carbon corrosion triggered platinum detachment; and (4) influencing transport property of the soluble platinum species (SPS) which may redeposit. Strict control of the lamination conditions is needed in order to avoid damage of the polymer and degradation of the catalyst.