Degradation Acceleration-Factor Analysis for Platinum Group Metal (PGM)-Free Polymer Electrolyte Fuel Cell Cathodes

Abstract

This work explores designs and methods that can mitigate degradation and can be used to expand models to predict PGM-free fuel cell degradation due to voltage cycling during accelerated stress tests (AST) and constant potential holds, specifically current density loss over time. The motivation behind investigating degradation mechanisms is that most of the recent advances have mostly focused on enhancing initial electrocatalytic activity, and not on catalyst stability. Advancements in catalyst stability are less substantial and are well below the level for commercialization. The objective is to determine the impact of the operating point on degradation rate in membrane electrode assemblies (MEAs) and to perform time-efficient evaluation of degradation acceleration factors on a single MEA. The preliminary AST cycling results show that reducing temperature and upper potential cycling limit considerably reduces degradation rates. This work can help identify operating points that optimize between performance and durability using empirical data. Ultimately, the correlations extracted from this work can be applied into drive-cycle models for PGM-free catalysts for simulation-based lifetime performance forecasting.This work was partially supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy under grant DE-0008440 (Prime: University of Kansas).