科研之友
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摘要
The durability of proton exchange membrane fuel cell (PEMFC) is a key factor affecting its practical application in the area of transportation, especially in the complex operating conditions. Therefore, improving the durability of PEMFC is very important, and it is essential to understand the performance degradation mechanism. In the PEMFC stack, the performance degradation of membrane electrode assembly (MEA) plays a decisive role in the performance degradation of the stack. Based on this opinion, we conduct a long-term cycling test for a 10 kW stack under a simulated operation conditions lasting for over 2,000 h. It is found that the performance of the stack has been attenuated obviously after the operating cycle test. The features and rule of the degradation have been analyzed. To find the reasons and mechanism for degradation, we carefully analyze the changes of the MEA and other components before and after the operating cycle testing, including the structure changes of the catalyst layer and the gas diffusion layer, the size changes of platinum nano-particles and electrochemistry surface area (ECSA) of the catalyst, the resistance changes of the stack (measured by EIS), etc. From the analysis results, it is found that the attenuation of MEA plays a crucial role for the degradation of stack. After a long-term testing, the size of the Pt particles grows larger, dissolution and migration of the Pt occur, the structure of the catalyst layer is destroyed and so on, all of which results in the degradation and fail of MEA and stack. The results of this work will be helpful to understand the attenuation rule and mechanism of large PEMFC stack, and it is meaningful for the researchers to improve the durability of PEMFC. ? 2023 Scientia Sinica Informationis.
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