Improved, high conductivity titanium sub-oxide coated electrodes obtained by Atmospheric Plasma Spray

• Titanium sub-oxide coatings were obtained by Atmospheric Plasma Spray.
• Coated samples exhibited good mechanical properties.
• Coated samples showed an increased range of operation than uncoated electrodes.
• Coated samples had higher electrical conductivity compared to standard electrodes.

Coatings based on reduced stoichiometries of titanium dioxide obtained by Atmospheric Plasma Spray are presented for their application as electrodes in devices such as lead acid batteries, redox flow batteries and electrochemical reactors. A study of their microstructure, composition and mechanical properties is first presented in this paper to show that the layers are compact, free of cracking and well adhered to the substrate. The presence of Magnéli phase oxides, particularly Ti8O15 was identified in the coatings, which enhances their electrical conductivity. In order to understand the behaviour of this material as an electrode, an electrochemical analysis of the coatings was also done. The coated samples showed higher oxygen and hydrogen evolution overpotentials and lower electrochemical corrosion compared to typically used commercial stainless steel and carbon–polymer composite electrodes.