Improved corrosion resistance and electrical characteristics of titanium, with atomic layer deposited (ALD) TiOx coating

• Voltage reduced for Ti anodization at elevated temperature. • ALD TiO x forms an effective oxygen diffusion barrier layer hence to prevent further oxidation of titanium. • ALD TiO x coating reduces corrosion of titanium in PEM electrolyzers at low pH. • Five orders of magnitude increase in current density with ALD TiO x -coated titanium. Titanium (Ti), widely used in proton exchange membrane (PEM) based water electrolyzers, is prone to oxidation and related corrosion given the high operating voltages (>2 V) and low pH (⩽5) conditions. Here, it is shown that a thin layer of ALD (atomic layer deposition) TiO x can serve as a barrier for drastically reducing the corrosion of Ti. The robustness of the coatings was evaluated at high potentials (2.4 V vs. RHE – reversible hydrogen electrode), in low pH and at elevated temperature (80 °C). A low TiO x dissolution rate (<∼5 nm year −1 ) along with five orders of magnitude enhanced current density, was observed for the ALD TiO x coated Ti compared to uncoated Ti.