Performance Degradation of Proton Exchange Membrane Fuel Cell Caused by an Accelerated Stress Test

Abstract

AbstractProton exchange membrane fuel cell (PEMFC) experiences inevitably performance decay due to various mechanisms. Among those, carbon corrosion is extremely detrimental. In this study, an accelerated stress test (AST) is conducted to a single cell to mimic the conditions when carbon corrosion occurs. The cell performance is characterized intermittently, and the experiment results show although electrochemical active area (ECA) decreases continuously from beginning‐of‐life (BOL) due to carbon corrosion at catalyst layer (CL), kinetic degradation is not apparent until AST 3 h. After that, kinetic loss increases progressively, while ohmic loss increases continuously. However, due to decrease of water generation under voltage‐controlled condition, or enhancement of water removal by phase change induced flow (PCI) under current‐controlled condition, the mass transport is slightly improved at later period of AST. To confirm such variation of mass transport loss, cell performance and EIS are measured at reduced air relative humidity (RHc) and reduced air flow rate. Both cell performance and EIS results show that in a degraded fuel cell, reduced air RHc and higher air flow rate are beneficial to cell performance. Hence, more sophisticated water management strategies for PEMFCs is recommended for different periods in their lifetime for a fuel cell stack.