Lu Congda, Shi Fengye, Jin Jing, Peng Xiang
Key Laboratory of E&M, Zhejiang University of Technology, Hangzhou 310014, China.
Materials (Basel). 2019 Mar 18;12(6):899. doi: 10.3390/ma12060899.
Research on the conductivity and corrosion resistance of stainless steel bipolar plates in a proton exchange membrane fuel cell (PEMFC) is commonly performed in a normal-temperature environment (about 20 °C). However, these fuel cells must function in low-temperature environments (lower than 0 °C) in some conditions, such as in vehicle fuel cells and in portable power supplies that operate during the winter in northern China. Stainless steel bipolar plates have higher requirements in terms of their hydrophobic and anti-icing properties, in addition to needing high conductivity and corrosion resistance. In this study, carbon nanotubes (CNTs) are grown on the surface of 304 stainless steel (304 SS) without a catalyst coating by plasma-enhanced chemical vapor deposition (PECVD), which is a simple and cheap method that allows stainless steel to be used as bipolar plates in low-temperature environments. The Raman spectroscopy and scanning electron microscopy (SEM) results show that the CNTs grown on the surface of 304 SS have different morphologies. The stainless steel samples with different CNT morphologies are tested by hydrophobicity and in situ icing experiments to prove that vertical CNTs can achieve a superhydrophobic state and have good anti-icing properties. The interfacial contact resistance (ICR) of the bare 304 SS and the 304 SS with vertical CNTs is compared by voltammetry, and then the corrosion resistances of both types is compared in a simulated PEMFC environment via a three-electrode system. Consequently, the ICR of the 304 SS with vertical CNTs was lower than the bare 304 SS. The corrosion potential was positive, and the corrosion current density was greatly reduced for the stainless steel with vertical CNTs grown directly on its surface when compared with the bare 304 SS. The experimental results show that vertical CNTs have good application prospects as bipolar plates for PEMFCs in low-temperature environments.
质子交换膜燃料电池(PEMFC)中不锈钢双极板的导电性和耐腐蚀性研究通常在常温环境(约20°C)下进行。然而,这些燃料电池在某些条件下必须在低温环境(低于0°C)中运行,例如车辆燃料电池以及中国北方冬季运行的便携式电源。不锈钢双极板除了需要高导电性和耐腐蚀性外,对其疏水性和抗结冰性能也有更高要求。在本研究中,通过等离子体增强化学气相沉积(PECVD)在无催化剂涂层的304不锈钢(304 SS)表面生长碳纳米管(CNT),这是一种简单且廉价的方法,可使不锈钢用作低温环境下的双极板。拉曼光谱和扫描电子显微镜(SEM)结果表明,在304 SS表面生长的CNT具有不同的形态。对具有不同CNT形态的不锈钢样品进行疏水性和原位结冰实验测试,以证明垂直排列的CNT可实现超疏水状态并具有良好的抗结冰性能。通过伏安法比较裸露的304 SS和具有垂直CNT的304 SS的界面接触电阻(ICR),然后通过三电极系统在模拟PEMFC环境中比较两者的耐腐蚀性。结果表明,具有垂直CNT的304 SS的ICR低于裸露的304 SS。与裸露的304 SS相比,直接在其表面生长垂直CNT的不锈钢的腐蚀电位为正,腐蚀电流密度大大降低。实验结果表明,垂直CNT作为低温环境下PEMFC双极板具有良好的应用前景。