Effects of Moisture Dehumidification on the Performance and Degradation of a Proton Exchange Membrane Fuel Cell

During the the proton exchange membrane fuel cell (PEMFC) operation, liquid water accumulates in the PEMFC, causing water flooding and performance degradation, especially at high current densities. Moisture dehumidification has been used to remove excess water in PEMFCs by forming a high water vapor concentration gradient between the inside and outlet of PEMFCs. This paper investigated the effects of moisture dehumidification on the performance of PEMFCs. The results indicated that the effect of moisture dehumidification on PEMFC performance depended on the water content in the PEMFC, and the positive effect was more evident under high current density, high relative humidity and high pressure. Moreover, moisture dehumidification is beneficial to alleviate the degradation of the catalytic layer. When there was no exhaust gas condensation, large-area fractures and loss occurred in the catalytic layer after 100 h of operation, and the ECSA was reduced by 22.28%. There was only a slight reduction in the thickness of the catalyst layer with moisture dehumidification, and the ECSA was only reduced by 1.82%. Therefore, the degree of moisture dehumidification should be adjusted according to the water content inside the PEMFC in actual operation.