At the beginning of the project, improvement of the implementation of gaseous water transport in the FAST-FC model was started. Literature was reviewed, and it was found that published data showed a large value span for key parameters. It was found that specific project characterisation was required in order to have representativeness for thin layers. The final model describes water transport through chemical potential gradient, liquid water pressure gradient and electroosmotic drag. The implemented model was shown to describe water uptake and release in dynamic vapor sorption experiments well.
An extensive characterisation package was established at month 6 of the project, this was important for the verification of the production of thin layers in the project. Characterisation of the SoA materials was performed and eventually progressed towards characterisation of new materials. In addition to electrochemical properties (e.g. voltage loss breakdown), with uncertainty limits, physical parameters (e.g water uptake), SEM imaging of thin membrane cross sections and graded layers with varying ionomer content (µXRF sulfur mapping) show that characterisation methods of materials is well established and ready to study the new layers developed within the project.
For the development of layers, several manufacturing techniques have been explored. For 10 and 8 µm membranes, focus has been on production consistency with respect to layer quality consistency. For additive layer manufacturing, manufacture of layers as thin as 6.5 µm has been achieved. For ultra-low loaded cathode, MEA performance data has been assessed for different catalysts. Understanding has been gained for disruptive deposition methods and work towards optimisation of spray coated layers. Further, deposition and performance assessment of initial layers with X-Y gradient has been completed.
Model validation work has been started through testing of MEAs with wet/dry and hot/cold operation.
