Ex-situ and in-situ degradation studies of MEAs used in 1 kW PEM fuel cell stack

Membrane Electrode Assembly (MEA) in a Polymer Electrolyte Membrane Fuel Cell (PEMFC) plays a fundamental role in the fuel cell system and degradation of it results in substantial performance losses. In this manuscript, the degradation study is carried out on a stack operated MEA of 50 cm2 area and coupled with 30 individual cells. Three MEAs (fresh, partially degraded and fully degraded) are disassembled from stack and characterized by electrochemical (cyclic voltammetry) and physical methods (TGA, XRD and SEM). TGA with DTG plot showed that MEA assembly majorly decomposes in the temperature range of 320-340 degrees C for Nafion membrane, 400-430 degrees C for carbon-supported catalyst and 650-750 degrees C for carbon-based GDL. In powder XRD characterization, a decrease in electrocatalyst sur-face area in the degradation sample was observed which also evidenced from the SEM micrographs. The average output voltage of 0.6 V is reduced to 0.42 V in the partially degraded (31.10%) 30th cell due to insufficient fuel for last cell. Catalyst particles are found to migrate outwards and located on the carbon backings was confirmed by ECSA (36% loss). The cell 26th is observed with 0.03 V in the fully degraded (94.43%) condition due to the high pressure in MEA for long-duration which compresses the cathodic side of the as-sembly resulting in cracking and creating space for the accumulation of water.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.