SAXS Analysis of Catalyst Degradation in High Temperature PEM Fuel Cells Subjected to Accelerated Ageing Tests

The loss in performance during fuel cell operation is one of the critical factors that hamper fuel cells commercialization. This paper presents a research activity related to high temperature polymer electrode membrane fuel cell (HT-PEMFC) degradation. The aim of the study is to investigate catalyst degradation of membrane electrode assemblies (MEAs) subjected to load cycles. Two HT-PEM MEAs have been subjected to accelerated ageing tests based on load cycling. The cycles profile has been chosen in order to enhance catalyst degradation. Both the tests show a fuel cell performance loss lower than 30 mV after 100,000 cycles at 600 mA cm−2. In order to analyze the catalyst evolution, synchrotron small angle X-ray scattering (SAXS) has been employed. The catalyst degradation of the two conditioned samples has been compared with the data obtained from a new MEA that has been used as reference sample. The SAXS results showed a mean size increase of the platinum nanoparticles up to the 100%.