During the first period, protocols for testing of materials as well as single cells and stacks were defined. They are available as a public report and have been shared with other CleanH2 projects related to MEA or stack development. In-situ and ex-situ tests to parametrize degradation models were extensively discussed between modelers and experimentalists. A multiscale modelling approach is being developed which describes cell performance and degradation processes from the mesoscale up to the single cell. Mesoscale models of the cathode catalyst layer have been developed. This is to consider local degradation reactions on the carbon support and the platinum catalyst nanoparticles. The micro-kinetics of the oxygen reduction reaction, carbon corrosion, and hydrogen peroxide formation are accounted. Moreover, a microstructure-resolved model of the catalyst layer degradation due to Ostwald ripening has been developed to link the material properties of the catalyst layer with the degradation rate. A continuum-scale catalyst layer degradation model was implemented to simulate the degradation-related change in platinum particle size distribution, the associated change in electrochemical surface area. Additionally, the dynamics of chemical membrane degradation was studied involving radical attack of the membrane. These degradation models will be coupled with the continuum-scale performance models to simulate their impact on performance. New testing protocols have been implemented into testbenches and validated and revised to achieve reproducibility among testing partners. A commercial MEA from IRD was used to realize first durability tests up to 1,500 h using the developed PEMTATIC HD-load cycle along with in-situ characterization protocols and ex-situ material analysis. Based on these tests the reproducibility was assessed. Eventually, issues were solved and good reproducibility was achieved. To develop heavy duty tailored MEAs, innovative materials from IMERYS, Heraeus and Chemours were used to design the first generation of project MEAs (Gen1 MEA). Moreover, promising candidate materials for Gen2 MEA were identified and fixed to start production of Gen2 MEA. Tests with Gen1 MEA will be used to improve degradation models. Model-based input will be used during implementation of adaptation when going from Gen2 to Gen3 MEA.
