酸性环境对PEM燃料电池弹性体垫片材料老化性能的影响

Effects of acidic environment on aging of elastomeric gasket material in PEM fuel cell

质子交换膜(PEM)燃料电池中弹性体垫片材料的持久性和稳定性对整个燃料电池的电化学性能有着重要影响。根据弹性体垫片材料在PEM燃料电池中所处酸性环境,配制了4种浓度不同的酸性试验溶液,研究弹性体垫片材料在该介质中的老化损伤情况。分别采用光学显微镜和傅立叶变换红外光谱(ATR-FTIR)仪观察了弹性体垫片材料在不同浓度溶液和不同老化时间后试样表面微观形貌变化和试样表面的化学成分变化。试验结果表明:老化时间和老化介质对弹性体垫片材料的损伤有着显著影响,其微观表面由平滑逐渐粗糙直至裂纹产生、增加;且随着时间和试验溶液浓度的增加,弹性体垫片材料的损伤程度增加。化学性能改变的机制主要是由于分子主链的水解和交联断裂。

The durability and the stability of the elastomeric gaskets had a significant effect on the electrochemical performance of the proton exchange membrane（PEM） fuel cell.Based on the acidic environment of PEM fuel cell,four test solutions were prepared.The aging of the elastomeric gaskets material exposed to the four solutions was studied for PEM fuel cell.The optical microscopy and attenuated total reflection Fourier transform infrared（ATR-FTIR） spectroscopy were used to study the topographical changes on the samples surface and the surface chemistry of the elastomeric gasket material before and after exposure to the acidic environments over time.The results showed that the aging time and the aging medium had a significant effect on the degree of the damage of the samples,and surface conditions were changed over time from initially smooth to rough,cracked surface and finally crack propagation.The higher the concentration of test solutions,the severer the material degraded.The degradation mechanisms of the material could be de-crosslinking and chain scissoring in the backbone in test environments.