Experimental Study on Critical Membrane Water Content of Proton Exchange Membrane Fuel Cells for Cold Storage at −50 °C

Membrane water content is of vital importance to the freezing durability proton exchange membrane fuel cells (PEMFCs). Excessive could cause irreversible degradation cell components and deteriorate performance lifetime. However, there are few studies on critical content, a threshold beyond which damage occurs, for cold storage PEMFCs. In this work, we first proposed method measuring using resistance extracted from measured high frequency (HFR) based finding that non-membrane part HFR constant within range 2.98 14.0. Then, freeze/thaw cycles were performed −50 °C 30 with well controlled content. After cycles, 8.2 7.7 exhibited no degradation, while those higher than showed significant decay. Electrochemical tests revealed electrochemical surface area (ECSA) reduction charge transfer increase main reasons degradation. These results indicate successful at 8.2.