Bohackova Tereza, Ludvik Jakub, Kouril Milan
Department of Metals and Corrosion Engineering, University of Chemistry and Technology Prague, Technická 5 Prague 6, 166 28 Prague, Czech Republic.
Materials (Basel). 2021 May 20;14(10):2682. doi: 10.3390/ma14102682.
The aim of this review is to summarize the possibilities of replacing graphite bipolar plates in fuel-cells. The review is mostly focused on metallic bipolar plates, which benefit from many properties required for fuel cells, viz. good mechanical properties, thermal and electrical conductivity, availability, and others. The main disadvantage of metals is that their corrosion resistance in the fuel-cell environment originates from the formation of a passive layer, which significantly increases interfacial contact resistance. Suitable coating systems prepared by a proper deposition method are eventually able to compensate for this disadvantage and make the replacement of graphite bipolar plates possible. This review compares coatings, materials, and deposition methods based on electrochemical measurements and contact resistance properties with respect to achieving appropriate parameters established by the DOE as objectives for 2020. An extraordinary number of studies have been performed, but only a minority of them provided promising results. One of these is the nanocrystalline β-NbN coating on AISI 430, prepared by the disproportionation reaction of Nb(IV) in molten salt, which satisfied the DOE 2020 objectives in terms of corrosion resistance and interfacial contact resistance. From other studies, TiN, CrN, NbC, TiC, or amorphous carbon-based coatings seem to be promising. This paper is novel in extracting important aspects for future studies and methods for testing the properties of metallic materials and factors affecting monitoring characteristics and parameters.
本综述的目的是总结在燃料电池中替代石墨双极板的可能性。该综述主要聚焦于金属双极板，其具备燃料电池所需的诸多特性，即良好的机械性能、热导率和电导率、可用性等。金属的主要缺点在于其在燃料电池环境中的耐腐蚀性源于钝化层的形成，这会显著增加界面接触电阻。通过适当的沉积方法制备的合适涂层系统最终能够弥补这一缺点，并使替代石墨双极板成为可能。本综述基于电化学测量和接触电阻特性，比较了涂层、材料和沉积方法，以实现美国能源部（DOE）设定的2020年目标参数。已经进行了大量研究，但其中只有少数取得了有前景的结果。其中之一是在AISI 430上通过Nb(IV)在熔盐中的歧化反应制备的纳米晶β-NbN涂层，其在耐腐蚀性和界面接触电阻方面满足了DOE 2020的目标。从其他研究来看，TiN、CrN、NbC、TiC或非晶碳基涂层似乎很有前景。本文的新颖之处在于提取了未来研究的重要方面以及测试金属材料性能的方法，还有影响监测特性和参数的因素。
