Decoupling Membrane Electrode Assembly Materials Complexity from Fuel Cell Performance through Image‐Based Multiphase and Multiphysics Modelling

Abstract Proton exchange membrane fuel cells (PEMFCs) are important clean energy technology, yet the material and structural complexity of their membrane electrode assemblies (MEAs) can hamper the development of next‐generation structures, as even a subtle change to one component can have a significant impact on others. Mathematical modelling of PEMFC MEAs proves to be one of the few techniques able to decouple this complexity, but the available models are commonly based on over‐simplified structures meaning they are less able to inform material design. In this study, an advanced image‐based modelling approach is developed to reveal the interplay of material changes in PEMFC MEAs. Using high‐temperature PEMFCs as an example system, advanced structural imaging techniques are used to produce a detailed 3D MEA reconstruction which forms the basis for the multiphase and multi‐physics model. This allows both the prediction of cell performance and the decoupling the impact of changes to individual structures or components (such as membrane pores, catalyst cracks, and phase migration), on cell behaviour. These phenomena can then be selectively ‘re‐coupled’ to deconvolute the interplay of different materials employed within operational cells. The resulting insights provide a mechanistic understanding of MEA performance, guiding the design and optimisation of future PEMFCs.