Preparation and properties of conductive Ti4O7 surface coating for Ti bipolar plates of proton exchange membrane fuel cells

Focusing on the special electrical conductivity and corrosion resistance of Ti4O7, this work proposes for the first time to reduce TiO2 film grown in situ on Ti substrate in a high-temperature tube furnace by using Ti/TiO2 mixed powder as reducing agent to obtain Ti4O7 surface coating. By characterization, the surface of the coated sample is identified as a Ti4O7 coating, with a partially unconverted TiO2 present at the interface between the Ti substrate and the Ti4O7 surface coating. The electrochemical, water contact angle and surface contact resistance tests show that the Ti4O7 surface coating provides superior protection to the Ti bipolar plate in the simulated proton exchange membrane fuel cell cathode environment, and simultaneously improving the electrical conductivity and water contact angle of the sample.