钛双极板无定型碳涂层在PEMFC不同氟离子环境中的性能

Performance of Amorphous Carbon-Coated Titanium Bipolar Plate in PEMFC with Different Fluoride Ion Contents

摘要:

采用直流平衡磁控溅射在TA2基材表面制备了无定型碳涂层，并采用电化学和表面接触电阻测试分析了TA2基材和无定型碳涂层在质子交换膜燃料电池（PEMFC）不同F^-浓度环境中的耐腐蚀性和导电性。无定型碳涂层的耐腐蚀性和导电性均优于TA2基材，随着F^-浓度由1×10^-6 mol/L逐渐增加到1×10^-3 mol/L，TA2基材和无定型涂层的缺陷密度增加，试样耐腐蚀性均有所下降。在高F^-浓度环境中（1×10^-3 mol/L），无定型碳涂层在0.6 V电位下的腐蚀电流密度为0.68 μA/cm²，依然能够对基材形成良好的保护。此外，TA2基材表面制备无定型碳涂层后，试样的表面导电性有所提升，其界面接触电阻值由76.40 mΩ·cm²（TA2）下降至6.52 mΩ·cm²。

Abstract:

The amorphous carbon coating was synthesized on the TA2 substrate surface by direct current balanced magnetron sputtering. The corrosion resistance and conductivity of TA2 substrate and amorphous carbon coating were analyzed by electrochemical and surface contact resistance tests in proton exchange membrane fuel cell (PEMFC) with different F^- contents. The results show that the corrosion resistance and conductivity of amorphous carbon-coated TA2 alloy are better than those of bare TA2 substrate. When the F^- content is increased from 1×10^-6 mol/L to 1×10^-3 mol/L, the defect density of TA2 substrate and amorphous carbon coating is increased, indicating the decreased corrosion resistance of both materials. The amorphous carbon coating at potential of 0.6 V demonstrates the corrosion current density of 0.68 μA/cm² in the F^- environment with high content (1×10^-3 mol/L), still providing a good protection for TA2 substrate. Moreover, the amorphous carbon coating can also improve the surface conductivity of the TA2 substrate: the interface contact resistance decreases from 76.40 mΩ·cm² (TA2 substrate) to 6.52 mΩ·cm².