Development of membrane electrode assemblies (MEA) containing radical scavengers and innovative membranes with improved stability and electrochemical test in a single-cell

In this deliverable, a radical scavenger based on Pt supported on commercial CeO2 using the sulphite complex route, was prepared. A 30%Pt/CeO2 scavenger was obtained and characterized by XRD and TEM analises. Moreover, different procedures to realize bare and composite Aquivion based membranes, were investigated. A screening of parameters such as: casting solvents, post-casting thermal and acid treatments, annealing, was performed. The most suitable procedure was selected taking into account also the chemical physical characterizations results, in terms of water retention, IEC and proton conductivity. Two different loads (1 and 1,5wt.%) of SCAV (30% Pt/CeO2) were introduced into the membranes. Encouraging preliminary results in terms of degradation resistance were obtained on a completely in-house product (Aqu-SCAV AD72/25-11I) that has demonstrated a reduced mass loss into ex-situ degradation Fenton’s test, good Wup trend, high IEC and PC. Regarding the development of catalytic inks and electrodes with improved stability, an optimization of the ink dispersing agent was performed by selecting H2O as most appropriate. Furthermore, the introduction of Pt/CeO2 into the cathodic catalytic layer was carried out, evaluating two different configurations, intermixed and with an additive layer. The electrochemical tests, carried out in a single cell configuration, highlighted the intermixed configuration as the most promising, allowing to reach higher performance . A preliminary in-situ degradation test at OCV carried out on the MEA cointaining the Pt/CeO2 intermixed in the CL, demonstrated lower degradation in terms of stability and loss of performance, confirming the benefit due to the scavenger introduction