Study on the Durability of the Microporous Layer of Proton Exchange Membrane Fuel Cell During the Voltage Reversal Process

The electrochemical corrosion of the microporous layer at high potentials caused by start-up / shut down and voltage reversal is an important factor affecting the lifetime of proton exchange membrane fuel cells. At present, most of the corrosion research on the microporous layer was conducted by Ex situ constant potential test method to simulate the high potential of the voltage reversal process. Under Ex situ high potential, carbon in the microporous layer corrodes severely, and the contact angle was significantly reduced, which deteriorated the cell performance. However, the results by actual voltage reversal test are inconsistent with that by Ex situ constant potential test. In this paper, the durability of the microporous layer in the voltage reversal process was studied through the in situ test, and the influence mechanism of microporous layer before and after voltage reversal on cell performance was evaluated. Meanwhile, the results by in situ voltage reversal test and Ex situ constant potential test were compared. When the microporous layer was immersed in the electrolyte solution during Ex situ constant potential test process, the pre-sence of electrolyte solution will increase the proton conductivity, and accelerated the carbon corrosion rate, which was impossible in actual fuel cells. Therefore, the Ex situ constant potential test cannot simulate the actual voltage reversal process. In order to further prove this hypothesis, we designed a microporous layer impregnated Nafion electrolyte, and verified that the presence of electrolyte in the microporous layer can promote the occurrence of carbon electrochemical corrosion reaction at high potential during the actual voltage reversal process. © 2022 Cailiao Daobaoshe/ Materials Review. All rights reserved.