Structure majorization on the surface of microporous layer in polymer electrolyte membrane fuel cells to optimize performance and durability

Abstract Proton exchange membrane fuel cell (PEMFC) is regarded as a potential future power source for automotive applications. Microporous layer (MPL) enhances the output performance and durability of PEMFCs by regulating water management. In this study, the structure majorization on the surface of MPL is investigated for the first time. Polymethyl Methacrylate (PMMA), a kind of pore agent that can form specific size and regular shape, is used in this paper to create the special structure. Worldwide Harmonized Light-duty Test Cycle (WLTC) operating condition is used in durability tests, which is in line with the actual application conditions of PEMFC. The sample with smaller PMMA (MPL-S) exhibits predominant performance, maximum power density reaching 1.30 W/cm2 under the humidification of 100%RH (relative humidity). After online durability test, MPL-S best maintains its performance. The maximum power density of MPL-S only drops by 10.6% after 100 h durability test. Results can prove that water is uniformly guided into the structure and then discharged, not hindering the contact between the gas and active sites of the catalyst. The mass transfer resistance is reduced and the drainage capacity is improved. The majorization is instructive for water management research on MPL in PEMFCs and the durability under WLTC operating condition can be used as a reference for practical applications.