Microporous layer (MPL) material structural modifications for enhanced efficiency and durability of proton exchange membrane fuel cells (PEMFCs): Toward sustainable maritime energy solutions

Decarbonization of the maritime propulsion and auxiliary power systems require the high-efficiency, zero-emission technologies. Key to this transition are the proton exchange Membrane Fuel Cells (PEMFCs); however, their stability in the long-term and water management ability is limited by the presence of suboptimal Microporous Layer (MPL) designs. In this work, a detailed, simulation-based optimization of MPL structures has been provided to work with marine operating conditions, particularly the interaction between porosity gradient, pore-size distribution, and hydrophobic binder ratio. Four new MPL configurations, including gradient-porosity, dual-layer, nano-structured and hydrophobic-optimized, were systematically evaluated using a coupled multiphysics model, which included electrochemical kinetics, two-phase flow and thermal fields as compared to a traditional reference MPL design. A simultaneous increase in power density of 17.8 %, a 22 % reduction in flooding incidence, and an extended lifespan of 6700 h were realized in the optimized nano-structured MPL. Increased diffusivity of oxygen, better capillary control and uniform distribution of thermal loads all reduced ohmic and activation losses. The findings demonstrate a direct relationship between multi-parameter stability and microstructural refinement, which provides a predictive model of the design of the next generation PEMFCs in the maritime systems.