PEMFC用不锈钢极板的电化学表面改性研究

Research on electrochemical surface modification of stainless steel polar plates for PEMFC

极板材料及其相关技术是质子交换膜燃料电池(PEMFC)技术的核心之一,其性能高低对燃料电池的性能和成本都有着直接影响。通过电化学方法,对不锈钢金属极板进行表面改性处理;应用腐蚀性能实验、界面接触电阻测试和X射线光电子光谱(XPS)分析等方法,研究了表面改性对不锈钢金属极板性能的影响。实验结果表明:电化学表面改性技术可以使不锈钢金属极板表面形成的氧化膜更薄,降低其界面接触电阻;有利组分Cr的含量及其高价化合物CrO3增加,不利组分Fe的含量减少,使极板耐腐蚀性能得到提高,经过在PEMFC模拟阴极/阳极环境条件下1000h耐久性评价后,腐蚀电流为10-6A·m-2数量级;因此电化学表面改性的不锈钢金属极板是PEMFC极板材料的一种良好选择。

The material of polar plates is one of the key technologies for PEMFC, which not only influence on the performance of PEMFC, but also on the cost of PEMFC, The electrochemical surface-modified stainless steel plate was proposed as a polar plate for PEMFC. The effects of surface modification was evaluated by using the methods of corrosion tests, interfacial contact resistance measurement and XPS analysis. The results show that the oxides film on the surface of stainless steel becomes thinner after electrochemical treatment, And interfacial contact resistance of the stainless steel is reduced after the surface modification,According to the XPS results, the content of Cr/CrO3 increased and the content of Fe decreased on the surface after electrochemical treatment, The changes in chemical content on the surface results the improvement of corrosion-resistance. The corrosion current in the order of 10^-8 A·cm^-2 was achieved after 1 000 h durability evaluation in the simulated PEMFC cathode/anode environment. Therefore, the electrochemical modified stainless steel metal plate will be a good candidate for PEMFC polar plates.