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

Abstract

Focusing on the special electrical conductivity and corrosion resistance of Ti 4 O 7 , this work proposes for the first time to reduce TiO 2 film grown in situ on Ti substrate in a high-temperature tube furnace by using Ti/TiO 2 mixed powder as reducing agent to obtain Ti 4 O 7 surface coating. By characterization, the surface of the coated sample is identified as a Ti 4 O 7 coating, with a partially unconverted TiO 2 present at the interface between the Ti substrate and the Ti 4 O 7 surface coating. The electrochemical, water contact angle and surface contact resistance tests show that the Ti 4 O 7 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. • A novel preparation method of Ti 4 O 7 coating is proposed. • Uniform and dense Ti 4 O 7 coating on Ti substrate is obtained in a short time. • Ti 4 O 7 coating maintains excellent corrosion resistance in simulate PEMFC cathode environment . • The Ti 4 O 7 coating exhibits high conductivity and hydrophobicity.