Quantification and evolution on degradation mechanisms of proton exchange membrane fuel cell catalyst layer under dynamic testing conditions

The catalyst layer is one of the core components of the Proton Exchange Membrane Fuel Cell (PEMFC). Studying its degradation mechanism is very important to improve the durability of PEMFC. Therefore, the degradation of the catalyst layer after the 100 h, 225 h, and 650 h durability tests are studied quantitatively in this paper. The results show that the agglomeration of Pt particles is the main reason for the degradation of the catalyst layer in the first 100 h, accounting for 80%. Catalyst dissolution and the loss of proton connectivity caused by the ionomer are the main factors for the degradation of the catalyst layer between 225 and 650 h, which increases from 23% in the initial stage to 46%. In addition, the corrosion degree of the carbon support inside the catalyst layer gradually intensified with the test time. This study reveals the dominant degradation mechanism of the catalyst layer in different degradation stages and the evolution of the whole degradation process, which has important guiding significance for the structural design of the catalyst layer for long-life fuel cells.