Self‐Catalyzed Rechargeable Lithium‐Air Battery by in situ Metal Ion Doping of Discharge Products: A Combined Theoretical and Experimental Study
Mengwei Yuan, Zemin Sun, Han Yang, Di Wang, Qiming Liu, Caiyun Nan, Huifeng Li, Genban Sun, Shaowei Chen
Abstract
Lithium‐air battery has emerged as a viable electrochemical energy technology; yet a substantial overpotential is typically observed, due to the insulating nature of the discharge product Li 2 O 2 that hinders the reaction kinetics and device performance. Furthermore, finite solid–solid/–liquid interfaces are formed between Li 2 O 2 and catalysts and limit the activity of the electrocatalysts in battery reactions, leading to inadequate electrolytic efficiency. Herein, in‐situ doping of Li 2 O 2 by select metal ions is found to significantly enhance the lithium‐air battery performance, and Co 2+ stands out as the most effective dopant among the series. This is ascribed to the unique catalytic activity of the resulting Co‐O x sites towards oxygen electrocatalysis, rendering the lithium‐air battery self‐catalytically active. Theoretical studies based on density functional theory calculations show that structural compression occurs upon Co 2+ doping, which lowers the energy barrier of Li 2 O 2 decomposition. Results from this study highlight the significance of in situ electrochemical doping of the discharge product in enhancing the performance of lithium‐air battery.