Investigation of Ageing Methods on Gas Diffusion Layers for HT-PEMFC Application

Gas diffusion layers (GDLs) are commonly used materials for polymer electrolyte membrane fuel cell (PEMFC) applications. Key role of the GDL is the distribution of reaction gases evenly from the bipolar plate to the catalyst layer and enabling the removal of product water. Especially challenging are elevated temperatures and acidic conditions for materials applied in high temperature (HT) PEMFCs. In this work, ex-situ ageing tests on GDLs were performed. First, the GDLs were aged in an electrochemical set-up in concentrated phosphoric acid (PA) at temperatures up to 160 °C. After ageing, the GDLs were analysed regarding their morphology and changes in elemental composition. The results show lower impact after ageing at constant potentials of 0.1 V, 0.8 V and OCV but a significant effect of increasing temperature and higher potential of 1.2 V as well as potential cycling. This is confirmed by morphological analysis.