PANI-ZIF-8/PA复合涂层的制备及其耐腐蚀性能研究

Synthesis of PANI-ZIF-8/PA Composite Coating for Improving Corrosion Protection Performance

摘要: 质子交换膜燃料电池(PEMFC)是目前应用于电动汽车中最具潜力的电力能源。作为PEMFC中的重要组成部分，双极板在分隔阴阳极板、收集热量和电流等方面发挥着重要作用。传统的燃料电池核心部件石墨双极板的工作环境(包括$S{O}_4^{2-}$ 、Cl⁻、F⁻、$HS{O}_4^{-}$ 、$C{O}_3^{2-}$ 等离子)容易使金属双极板产生阳极钝化现象，从而使质子膜燃料电池的工作寿命降低。人们通常会在双极板的表面涂覆导电涂层，如聚苯胺、聚吡咯等，以此来减缓双极板的腐蚀速率，但纯聚苯胺涂层附着力差、气孔缺陷等问题限制了其应用。本文采用三电极系统，将聚苯胺电沉积在不锈钢板上，然后将ZIF-8与丙烯酸树脂(PA)混合旋涂于聚苯胺涂层之上形成双层涂层，系统地研究了涂层的组成、结构和在PEMFC环境下的耐蚀性。结果表明，PANI-ZIF-8/PA复合涂层在模拟质子交换膜燃料电池环境中表现出比纯聚苯胺涂层更好的长期浸泡稳定性。耐蚀性的增强主要得益于ZIF-8/PA的引入增强了物理屏障效应和聚苯胺涂层的附着力。同时水接触角测试表明PANI-ZIF-8/PA复合涂层的亲水性相较于纯聚苯胺明显降低，进一步提高了涂层的耐腐蚀性。

Abstract: Proton exchange membrane fuel cell (PEMFC) is the most promising electric energy source currently applied in electric vehicles. As an important component in PEMFC, bipolar plates play an important role in separating cathode and anode plates, and collecting heat and current. The operating environment (including ions such as $S{O}_4^{2-}$ , Cl⁻, F⁻, $HS{O}_4^{-}$ , $C{O}_3^{2-}$ , etc.) of graphite bipolar plates, the core component of conventional fuel cells, tends to produce anodic passivation of the metal bipolar plates, which reduces the operating life of proton membrane fuel cells. People usually apply conductive coatings, such as polyaniline and polypyrrole, on the surface of the bipolar plates to slow down the corrosion rate of the bipolar plates, but the problems of poor adhesion and porosity defects of the pure polyaniline coatings limit their applications. In this paper, a three-electrode system was used to electrodeposit polyaniline on a stainless steel plate, and then ZIF-8 mixed with acrylic resin (PA) was spin-coated on top of the polyaniline coating to form a double-layer coating, and the composition, structure, and corrosion resistance of the coatings under PEMFC environment were systematically investigated. The results show that the PANI-ZIF-8/PA composite coating exhibits better long-term immersion stability than the pure polyaniline coating in a simulated proton exchange membrane fuel cell environment. The enhanced corrosion resistance is mainly attributed to the introduction of ZIF-8/PA which enhances the physical barrier effect and the adhesion of the polyaniline coating. Meanwhile, the water contact angle test shows that the hydrophilicity of the PANI-ZIF-8/PA composite coating is significantly reduced compared with that of the pure polyaniline, which further improves the corrosion resistance of the coating.