物理化学学报 >> 2010, Vol. 26 >> Issue (03): 595-600.doi: 10.3866/PKU.WHXB20100329

电化学 上一篇    下一篇

镀银-石墨涂层316L不锈钢双极板的电化学性能测试及表征

梁鹏, 徐洪峰, 刘明, 卢璐, 傅杰   

  1. 大连交通大学环境与化学工程学院, 辽宁 大连 116028
  • 收稿日期:2009-10-11 修回日期:2010-01-06 发布日期:2010-03-03
  • 通讯作者: 徐洪峰 E-mail:hfxu@fuelcell.com.cn

Electrochemical Performance Testing and Characterization of Silver-Plated and Graphite-Coated 316L Stainless Steel Bipolar Plates

LIANG Peng, XU Hong-Feng, LIU Ming, LU Lu, FU Jie   

  1. College of Environmental and Chemical Engineering, Dalian Jiaotong University, Dalian 116028, Liaoning Province, P. R. China
  • Received:2009-10-11 Revised:2010-01-06 Published:2010-03-03
  • Contact: XU Hong-Feng E-mail:hfxu@fuelcell.com.cn

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摘要：

316L不锈钢以其质轻, 价廉, 易加工成型以及良好的导电导热性能而成为极具潜力的质子交换膜燃料电池双极板材料, 但其在电池运行环境中仍有一定缺陷. 在阴极条件下不锈钢板易钝化, 增加了与碳纸扩散层间的界面接触电阻; 而在阳极条件下, 则由于金属离子的溶解, 污染了膜电极, 引起催化剂中毒, 从而降低电池输出功率, 影响电池性能. 本文采用喷涂技术在316L不锈钢表面制备导电石墨涂层, 测得其与Toray 060碳纸的接触电阻为80.6 mΩ·cm2. 如果在制备石墨涂层前预镀薄层银, 则可使其接触电阻降至19.8 mΩ·cm2. 因此，本文利用Tafel曲线、恒电位氧化等电化学方法, 对该镀银-石墨涂层316L不锈钢与原316L不锈钢和镀银316L不锈钢在模拟质子交换膜燃料电池阴、阳极工作环境条件下的耐腐蚀性能进行了研究. 结果表明, 镀银不锈钢和镀银-石墨涂层不锈钢较原不锈钢的腐蚀电位分别提高了0.49和0.35 V, 腐蚀电流密度下降1-2个数量级, 维持在10-6-10-7 A·cm-2. 而镀薄银钢板则因为银层较薄存在微孔, 使得部分不锈钢基体外露,形成腐蚀电池而更易于腐蚀.

关键词: 质子交换膜燃料电池, 双极板, 316L不锈钢, 石墨涂层, 镀银-石墨涂层

Abstract:

316L stainless steels are the most promising materials for use as bipolar plates in proton exchange membrane fuel cells (PEMFC) because of their low cost, light weight, convenience of machining, ease of shaping into thin sheets, excellent electrical conductivity, and their heat exchange properties. However, the interfacial contact resistance (ICR) between carbon paper and stainless steel was found to increase because of passive film formation in a PEMFC cathodic environment. Additionally, the catalyst was poisoned by the corrosion products of the bipolar plate in the PEMFC anodic environment and the output power of the cell decreased. We added a conductive graphite coating onto the surface of 316L stainless steel and found the ICR of the sample reached 80.6 mΩ·cm2. The ICR was only 19.8 mΩ·cm2 when a thin layer of silver was present between the 316L stainless steel and the graphite layer. Various electrochemical tests, such as Tafel curves and oxidation curves using steady potential, were used to study the corrosion behavior of the three samples (316L stainless steel, silver-plated 316L stainless steel, silver-plated and graphite-coated 316L stainless steel) in PEMFC environments. Results showed that compared to 316L stainless steel, the corrosion potential of the silver-plated and graphite-coated 316L stainless steel increased by 0.49 and 0.35 V, respectively and the corrosion current density decreased to 10 -6-10 -7 A·cm-2. The silver-plated sample was easily damaged as small holes in the silver-layer allowed parts of the stainless steel substrate to be exposed.

Key words: Proton exchange membrane fuel cell, Bipolar plate, 316L stainless steel, Graphite-coating, Silver-plating and graphite-coating