Doping Effects of Metals on Electrical Conductivity of TiO₂ from First-Principles Calculations

Titanium is promising candidates for bipolar plates in fuel cell, electrolysis, etc., due to the excellent corrosion resistance of titanium oxide (TiO 2 ). However, TiO 2 also possesses poor electrical conductivity and leads to high power losses, so that the conductivity of titanium needs to be further improved. In this work, the effect of thirty-nine metals on the conductivity of TiO 2 was studied based on the first-principles merged with the Boltzmann transport equation and Deformation potential theory. The results show that the conductivity meets the target of 100 S∙cm -1 proposed by the U.S. Department of Energy when TiO 2 doped with Cr, Sb, Ga, etc. The Sb-doped not only enhances carrier concentration, reduces relaxation time, but also improve the chemical bond. The intermediate bands induced by Au, W, Rh, etc. is a special conductivity enhanced mechanism.