Int. J. Hydrogen Energy, 47, 11622-11632 (2022) [pdf]

Controlling the Compactness and sp² Clusters to Reduce Interfacial Damage of Amorphous Carbon/316L Bipolar Plates in PEMFCs

Hao Li, Yang Xn, Keiji Komatsu, Peng Guo, Guanshui Ma, Peiling Ke, Kwang-Ryeol Lee, Hidetoshi Saito, and Aiying Wang
 

In proton exchange-membrane fuel cells, the compactness and composition of amorphous carbon (a-C) films directly affect the interface-induced degradation of a-C-coated metallic bipolar plates, but their roles and synergistic effects are ambiguous. In this study, by changing the working pressure, the compactness and composition of a-C are adjusted, and the relationship among the plasma state, microstructure, and performance of coated 316L stainless steel are studied. Results show that, at 2 mTorr, a high ionization degree of the plasma causes high compactness (highest density 2.52 g/cm³) and large sp² cluster size in a-C films, resulting in their best performance. At 11 mTorr, the low ionization degree causes their loose structure and large sp² cluster size. The possible galvanic coupling effect can result in serious interface damage and the highest Fe ions concentration of 13.05 ppm after a potentiostatic test. Thus, high compactness and large sp² cluster sizes should be obtained simultaneously to improve their performance.