Jianyu Wang,Luofu Min,Feifei Fang,Wen Zhang,Yuxin Wang
We report in this paper a simple method of coating very thin graphene film on titanium substrate, affording it markedly enhanced resistance to corrosion and much decreased electrical contact resistance under the environment of proton exchange membrane fuel cells (PEMFC). The graphene film is formed by electrodepositing graphene oxide (GO) on Ti sheet via normal pulse voltammetry , followed by reducing the deposited GO at 500 °C in hydrogen atmosphere. The resultant graphene film, with a thickness of only around 50 nm, evenly covers and covalently bonds to the Ti sheet, as revealed by SEM, Raman and XPS . Both potentiodynamic and potentiostatic tests of the graphene coated Ti (G/Ti) sample are conducted under simulated chemical environment and electrode potentials of PEMFC. Under all the circumstances, the corrosion currents of G/Ti sheet are in the order of 10 −7 A/cm 2 , significantly less than that of bare Ti sheet. Moreover, the coated graphene film on Ti sheet leads to a much lower and more stable interfacial contact resistance (ICR) of around 4 mΩ cm 2 . These results mean that the G/Ti sheet meets the U.S. DOE target of 2020 for PEMFC bipolar plates (BP) in terms of both the corrosion and electrical resistance. Therefore, the G/Ti sheet appears to be a very promising BP material in PEMFC.
Yirui Lu,Linhan Jia,Daijun Yang,Yu Leng,Jie Chen,Pingwen Ming,Junying Min,Xiangmin Pan
Understanding the corrosion behavior of bipolar plates (BPPs) and their coatings under dynamic load cycling (DLC) is crucial for the commercial application of proton exchange membrane fuel cells (PEMFCs). This study employs a PEMFC stack comprising titanium anode plates coated with ruthenium oxide to investigate the degradation of these components after DLC testing, specifically under conventional operating conditions (75 °C for 1000 and 3000 h) and accelerated aging conditions (95 °C for 100 h). The corrosion behavior and degradation mechanisms of the coating and TA1 substrate in Ti-BPP samples after various DLC tests are analyzed using electrochemical tests, morphological evaluations, and elemental characterization. The results indicate that the morphological and structural changes in BPP after different DLC tests show significant differences. The coating suffered severe damage under high temperature aging conditions. The generation and dissolution of metal oxides on the BPP surface, along with the corrosion and exfoliation of the coating, resulted in increased surface roughness, decreased corrosion resistance, reduced electrical conductivity, and weakened bonding strength between the coating and the BPP substrate. These findings offer insights for optimizing coating materials under high temperature operating conditions and for assessing the corrosion resistance of metallic BPPs.
危险品化学品经营许可证（带存储）