RuO<sub>2</sub> Monolayer: A Promising Bifunctional Catalytic Material for Nonaqueous Lithium–Oxygen Batteries

2016-03-09T00:00:00Z (GMT) by Le Shi Ao Xu Tianshou Zhao
Rutile RuO<sub>2</sub> 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 RuO<sub>2</sub>’s polymorph, RuO<sub>2</sub> monolayer, has been less studied. In this work, we study the catalytic activities of both rutile RuO<sub>2</sub> and RuO<sub>2</sub> monolayer for ORR and OER in the battery using density functional theory method. Computational results show that the RuO<sub>2</sub> monolayer exhibits a higher catalytic activity than the rutile RuO<sub>2</sub> does. More interestingly, it is found that during discharge a similar lattice structure between RuO<sub>2</sub> monolayer and Li<sub>2</sub>O<sub>2</sub> {0001} surface can induce the formation of crystallized Li<sub>2</sub>O<sub>2</sub> with the conductive {0001} surface exposed, whereas during charge the RuO<sub>2</sub> monolayer can attract the remaining Li<sub>2</sub>O<sub>2</sub> to its surface spontaneously, thus maintaining the solid–solid reaction interface. Our results suggest that the RuO<sub>2</sub> monolayer is a promising catalytic material for nonaqueous lithium–oxygen batteries.