Niobium doped amorphous carbon film on metallic bipolar plates for PEMFCs: First principle calculation, microstructure and performance
Niobium doped amorphous carbon film on metallic bipolar plates for PEMFCs: First principle calculation, microstructure and performance
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用于质子交换膜燃料电池的金属双极板上的铌掺杂非晶碳薄膜：第一原理计算、微观结构和性能
DOI：
10.1016/j.ijhydene.2018.12.040
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发表时间：
2019-01-28
影响因子：
7.2
通讯作者：
Lai, Xinmin
中科院分区：
文献类型：
--
作者：
Hou, Kun;Yi, Peiyun;Lai, Xinmin
由于质子交换膜燃料电池 (PEMFC) 具有更高的功率密度和更低的成本，金属双极板 (BPP) 是替代传统石墨 BPP 的有前途的候选者。表面涂层对于增强界面导电性和耐腐蚀性至关重要。非晶碳（a-C）薄膜引起了学术界和工业界的广泛关注。这项研究将铌 (Nb) 添加到 a-C 中，以进一步增强其性能。引入第一原理计算来研究铌掺杂导致的键和相的演化机制并指导涂层设计。然后，通过闭场非平衡磁控溅射离子镀（CFUBMSIP）方法沉积了一系列Nb掺杂a-C样品。通过SEM、XRD、拉曼光谱和XPS 系统地表征了微观结构。还测试了界面接触电阻（ICR）和电化学腐蚀，以评估 Nb 掺杂的效果。在中等 Nb 掺杂的 a-C 薄膜中观察到较高的 C-sp(2)/C-sp(3) 比率。结果，ICR 从初始值 4.41 m Omega.cm(2) 降至 1.22 m Omega.cm(2)。此外，Nb的掺杂还细化了晶粒尺寸，增加了膜层的致密性，有利于耐腐蚀性能。反映相对防腐性能的Rct从1.8×10(6)Omega.cm(2)增加到3.29×10(6)Omega.cm(2)。此外，0.84 V（vs. SHE）动电位极化下的电流密度为3.59 x 10(-7) A/cm(2)，低于a-C薄膜的4.59 x 10(-7) A/cm(2)。此外，0.84 V（vs. SHE）恒电位极化下的电流密度也表现出相同的趋势。掺铌 a-C 涂层的增强性能将促进 PEMFC 金属 BPP 的商业化。 (C) 2018 年由 Elsevier Ltd 代表 Hydrogen Energy Publications LLC 出版。
Metallic bipolar plates (BPPs) are a promising candidate to replace conventional graphite BPPs due to higher power density and lower cost in proton exchange membrane fuel cells (PEMFCs). Surface coating is essential to enhance interfacial conductivity and corrosion resistance. Amorphous carbon (a-C) films have attracted broad attention from both academia and industry. This study incorporated Niobium (Nb) into a-C to further enhance its performance. First principle calculation was introduced to investigate the evolution mechanism of bond and phase by Nb doping and instruct the coating design. Then, a series of Nb-doped a-C samples were deposited by closed field unbalanced magnetron sputtering ion plating (CFUBMSIP) method. The microstructure was systematically characterized by SEM, XRD, Raman spectrum, and XPS. Interfacial contact resistance (ICR) and electrochemical corrosion were also tested to evaluate the effect of Nb doping. A higher C-sp(2)/C-sp(3) ratio was observed in a-C film with moderate Nb doping. As a result, the ICR decreased to 1.22 m Omega.cm(2) from initial value of 4.41 m Omega.cm(2). Besides, the doped Nb also refined grain size and increased the film compactness, which was beneficial for corrosion resistance. Rct, which reflects the relative anticorrosive property, was increased from 1.8 x 10(6) Omega.cm(2) to 3.29 x 10(6) Omega.cm(2). Moreover, the current density in 0.84 V (vs. SHE) potentiodynamic polarization is 3.59 x 10(-7) A/cm(2), lower than 4.59 x 10(-7) A/cm(2) of a-C films. Besides, the current density in 0.84 V (vs. SHE) potentiostatic polarization shows the same tendency. The enhanced performance of Nb-doped a-C coatings would advance the commercialization of metallic BPPs for PEMFCs. (C) 2018 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.