RuO2 Monolayer: A Promising Bifunctional Catalytic Material for Nonaqueous Lithium-Oxygen Batteries

Rutile RuO2 has been widely regarded as an excellent catalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in nonaqueous lithium-oxygen batteries and achieved superior performance, but the catalytic activity of RuO2's polymorph, RuO2 monolayer, has been less studied. In this work, we study the catalytic activities of both rutile RuO2 and RuO2 monolayer for ORR and OER in the battery using density functional theory method. Computational results show that the RuO2 monolayer exhibits a higher catalytic activity than the rutile RuO2 does. More interestingly, it is found that during discharge a similar lattice structure between RuO2 monolayer and Li2O2 {0001} surface can induce the formation of crystallized Li2O2 with the conductive {0001} surface exposed, whereas during charge the RuO2 monolayer can attract the remaining Li2O2 to its surface spontaneously, thus maintaining the solid-solid reaction interface. Our results suggest that the RuO2 monolayer is a promising catalytic material for nonaqueous lithium-oxygen batteries.