垫片材料在模拟PEM燃料电池环境下损伤研究

Study on degradation of a gasket material in simulated PEM fuel cell environments

质子交换膜(PEM)燃料电池需要弹性体垫片来密封阳极和阴极的反应气体(氢气和氧气/空气),燃料电池在长时间运行过程中,垫片材料性能的稳定性对燃料电池密封性能和电化学性能至关重要。在模拟的PEM燃料电池环境下,利用光学显微镜观察试样暴露在模拟的PEM燃料电池环境下表面的损伤情况,采用X射线光电子能谱技术(XPS)研究弹性体垫片材料在模拟的燃料电池环境下的损伤及损伤机理。实验结果表明,材料暴露在模拟的PEM燃料电池环境下发生损伤,试样质量损失随着暴露时间的增加而增加;光学显微镜观察表明:试样表面形貌发生了明显变化,其损伤过程表现为试样表面从光滑到粗糙,到裂纹产生,再到裂纹扩展;XPS实验结果表明,试样表面的化学成分发生了明显的变化。

Proton exchange membrane（PEM） fuel cells require elastomeric gaskets in each cell to keep the reactant gases（hydrogen and oxygen/air） within their respective regions.During the long-term operation,the chemical and mechanical stability of gasket materials are critical to both sealing and electrochemical performance of fuel cells.In this paper,the optical microscopy was used to observe the topographical changes on the sample surface for the samples after exposure to the simulated PEM fuel cell environments.X-ray photoelectron spectroscopy（XPS） was employed to study the surface chemistry of the elastomeric gasket material before and after exposure to the simulated fuel cell environments over time.The test results show that the gasket material degrades by weight loss for the samples expose to the simulated PEM fuel cells,and the weight loss increases with the exposure time.The optical microscopy shows that the surface conditions of the samples change over time from initially smooth to rough,crack appearance and finally crack propagation.The XPS result indicates that the surface chemistry changes significantly as a manifestation of the chemical degradation of the gasket material.