Effective Testing Matrix for Studying Membrane Durability in PEM Fuel Cells: Part I. Chemical Durability

Abstract

In order to advance membrane technologies for PEM fuel cells, it is critical to establish an effective testing matrix, which includes tests that target specific mechanisms of chemical and mechanical durability, as well as tests that can challenge the membrane with combined failure mechanisms. Furthermore, the tests should be both accelerated and realistic. In studies of membrane chemical durability, it was discovered that using regular test cells resulted in highly non-uniform membrane degradation in the active area. This compromised the quantitative value of the data and prevented the use of average fluoride release rate over the entire cell as an accurate measure of the chemical degradation rate of the membrane. Therefore, a homogeneous environment was needed for more quantitative studies of membrane chemical durability. Among various options, operation at OCV using standard test cells and operation under a load using high gas stoichiometries with a uniform test cell were chosen. Test results indicate that combinations of these test protocols enable the dependable selection of more chemically durable membranes and also provide quantitative data to assist understanding of degradation mechanisms in fuel cells under various operation conditions.