Improved corrosion resistance and electrical characteristics of titanium, with atomic layer deposited (ALD) TiOx coating
Kesong Wang, Adam Paxson, Thomas Valdez, Ahmet Gün Erlat, Ping‐Che Lee, SeongUk Yun, Andrew C. Kummel, Prabhakar R. Bandaru
Abstract
• 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.