Patterned Design of Porous Carbon Materials as Microporous Layers to Enhance Fuel Cell Performance Over a Wide Humidity Range

Abstract

Microporous layers play a crucial role as the main component of membrane electrode assembly (MEA) in facilitating effective water management for proton exchange membrane fuel cells (PEMFCs), which is vital for maintaining optimal performance in a wide humidity range. Herein, Zn-based zeolitic imidazolate framework (ZIF-8)-derived material (ZDM) as a porous carbon material is first introduced to construct the microporous layer (MPL). With promoted gas permeability, water management, and electrical conductivity, MPL equipped with a ZDM layer exhibits superior performance, surpassing commercial MPLs throughout the range of 30‒100% RH. The peak power density of an H2/air PEMFC at 70% relative humidity (RH) utilizing a ZDM MPL achieves 1.32 W cm-2, which is 3.3 times that of commercial MPL. To further improve water management in PEMFCs, a unique striped dual MPL is designed to boost the performance; the peak power density achieves 1.50 W cm-2 (H2/air) with a low total Pt loading of 0.3 mgPt cm–2 at 100% RH. The result demonstrates that the material and structural design of the MPL allows for the efficient operation of low Pt -loading PEMFCs over a wide humidity range.

Keywords: Microporous layers, PEMFCs, Water management, Porous carbon materials, Wide humidity range