Durability analysis of polymer electrolyte membrane fuel Cell's gas diffusion layer based on distribution relaxation time analysis: Influence of the presence or absence of a micro-porous layer

Abstract

The U.S. Department of Energy accelerated stress test carbon protocol emphasizes improving the durability of both the catalyst layer and the micro-porous layer (MPL) carbon support. This underscores the need for research focused solely on the degradation of the Gas Diffusion Layer (GDL). Traditionally, electrochemical impedance spectroscopy impedance data used to analyze resistance due to GDL durability has been interpreted through equivalent circuit models. However, this method simplifies simultaneous response and multiple models for the same data, which reduces the objectivity of the analysis. Therefore, this study analyzed the durability characteristics of GDLs with and without MPLs using distribution of relaxation times, a method less prone to subjectivity. In short, the results showed that substrates without MPL are more susceptible to performance degradation and loss, and highlighted the emergence of Warburg resistance due to limited diffusion under harsh environmental conditions.