Development of Ti bipolar plates with carbon/PTFE/TiN composites coating for PEMFCs

A highly corrosion resistant and conductive carbon/PTFE/TiN composite coating on Ti bipolar plates is prepared by a two-step hydrothermal and impregnation process. The composite coating exhibits a full coverage with uniformly distributed PTFE and TiN particles when 0.1 mol/L of glucose is used as carbon source and 10 wt % PFTE + 3 g/L TiN suspension as impregnating solution. The as-prepared composite coating film shows 0.009 μA cm −2 of corrosion current density and 13 mΩ cm 2 of ICR in the simulated solution of proton exchange membrane fuel cells, respectively. Meanwhile, the potentiostatic polarization test shows that the corrosion current density of the composite coating is below 1 μA cm −2 under real PEMFC working conditions of the cathode (0.6 V) and anode (−0.1 V). Additionally, the composite coating enhances hydrophobic property with a static contact angle of 120.2°and 115.5°before and after polarization test, respectively. In summary, the Ti substrate with carbon/PTFE/TiN composite coating shows a great potential application as bipolar plates of PEMFCs.