金属双极板在模拟直接甲醇碱性燃料电池环境中的电化学行为

Electrochemical behaviors of metal bipolar plate in simulated DMAFC environment

直接甲醇碱性燃料电池(DMAFC)由于采用了碱性电解质膜,许多在酸性介质中无法使用的非铂金属成为可选的催化剂已经引起了大家的普遍关注。双极板,特别是金属双极板作为DMAFC中一个关键材料对电池的输出性能起着重要的作用,其腐蚀性的大小决定了燃料电池的使用寿命长短。迄今为止,金属双极板在DMAFC中的研究国内外少见报道。本文对比研究了不锈钢316L和石墨作为双极板在模拟DMAFC中的电化学性能。动电位和电化学阻抗谱分析结果表明:不锈钢316L腐蚀电流低于石墨,其极化电阻明显高于石墨,恒电位实验结果与Tafel曲线分析结果一致,验证了动电位和电化学阻抗谱的实验结果。说明在碱性环境中,金属双极板与电解质溶液之间的反应活性比石墨双极板低,为拓宽不锈钢316L在DMAFC的应用奠定了理论基础。

Direct methanol alkaline fuel cell（DMAFC）has attracted a broad attention because of the possibility of using non-platinum catalysts. Bipolar plates are very significant components in fuel cells,whose corrosion resistance determines the fuel cell＇s life. While,application of metal bipolar plate in DMAFC has been rarely investigated. This paper reports a comparative study in the electrochemical behaviors of bipolar plates with 316L stainless steel and graphite in a simulated DMAFC environment were investigated. Results of potentiodynamic experiments and electrochemical impedance spectroscopy（EIS）showed that the bipolar plate corrosion current density of 316L is lower than that of graphite,and the polarization resistance of 316L is obviously superior to that of graphite. Results of potentiostatic experiments were consistent with the analysis of Tafel curve,which further verifies the results of potentiodynamic experiments and EIS. It can be concluded that the reactivity of 316L stainless steel in electrolyte solution is lower than that of graphite bipolar plate,which may make great contribution to the progress of DMAFC.