High-Performance Proton Exchange Membrane Fuel Cells Enabled by Highly Hydrophobic Hierarchical Microporous Carbon Layers Grafted with Silane

The employing of a microporous layer (MPL) with an appropriate pore size distribution and hydrophobicity between the carbon paper substrate and catalyst layer of proton exchange membrane fuel cells (PEMFCs) plays a decisive role in the management of gas transport and the crucial prevention of water flooding. However, enhancing the performance of PEMFCs by directly altering the structure of MPL has rarely been reported. The present work addresses this issue by fabricating hierarchical porous carbon (HPC) enabled MPLs via a dual template method employing zinc oxide and sodium chloride, and a silane-coupling agent is chemically grafted to HPC components of the MPL to improve water drainage instead of applying a conventional hydrophobic treatment. The physical and electrochemical properties of gas diffusion layers formed with different MPLs are analyzed, and the results indicate that the proposed MPL with excellent water drainage and efficient gas transport capability facilitates a higher output power density (863.62 mW cm–2) and lower mass transport impedance superior to a conventional MPL. This work provides a generic and feasible structure design for the development of MPLs that significantly improves the performance of PEMFCs.