期刊
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
卷 160, 期 4, 页码 F456-F463出版社
ELECTROCHEMICAL SOC INC
DOI: 10.1149/1.023306jes
关键词
-
资金
- Swiss Federal Office of Energy (SFOE) [102347]
Membrane defects, such as pinholes and cracks, are common failure modes in polymer electrolyte membranes. The elevated gas crossover at these defect sites is expected to accelerate membrane degradation locally. The defect site will expand, leading to premature cell failures. In order to understand the degradation pathway, degradation processes were analyzed at-membrane defects using mass spectrometry, synchrotron assisted X-ray tomographic microscopy and FM. spectro-microscopy, and thermochromic pigments. MEAs with artificially implemented membrane defects, 10 mu m in diameter, were operated in fuel cells under accelerated stress test conditions. The gas crossover was analyzed online using a tracer gas concept that allows for monitoring the evolution of the defect size. Chemical, mechanical and thermal degradation processes have been identified and investigated. A synergetic effect that results from the combination of the processes accelerates degradation, leading to an exponential increase of the gas crossover. Polymer fracturing, polymer melting, the formation of COOH groups, catalyst sintering, carbon corrosion and local temperatures of up to 140 degrees C were observed at membrane defects. Degradation processes are affected by the degradation side, gas crossover, gas composition, mechanical stress and the local inhomogeneities of the gas diffusion electrode. From the results, an overall degradation mechanism at membrane defects is formulated. (C) 2013 The Electrochemical Society. [DOI: 10.1149/1.023306jes] All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据