Oxygen Evolution Reaction on Pristine and Oxidized TiC (100) Surface in Li-O2 Battery

The oxidized TiC (100) surface has been constructed to compare surface stability and catalytic performance with the pure TiC (100) surface in Li-O-2 battery by first-principles calculations. The stable oxidized surface was determined by calculating the formation energies of TiC (100) surface under various O coverage rates. The interfacial catalytic models of LixO2 (x = 2, 1, and 0) molecules adsorbed on pristine and oxidized TiC (100) surface were used to simulate the OER process. The results of thermodynamics calculation indicate that the oxidized TiC (100) surface has smaller O-2 evolution barrier and lower charge voltage. The electron-withdrawing O layer plays an important role in increasing charge transfer from O-2(x-) (x = 2, 1, and 0) to the substrate, which is helpful for O-2(2-) oxidation and Li-O bond activation. The theoretical results have well verified experimental findings of the oxidized TiC surface as the potential state of TiC cathode material in the Li-O-2 battery. The surface-modified strategy of the stronger electron-withdrawing layer is proposed to improve OER catalysis in the Li-O-2 battery, which provides a way for designing more active catalysts.