Adjusting the 3d Orbital Occupation of Ti in Ti<sub>3</sub>C<sub>2</sub> MXene via Nitrogen Doping to Boost Oxygen Electrode Reactions in Li–O<sub>2</sub> Battery
Haoyang Xu, Ruixin Zheng, Dayue Du, Long‐Fei Ren, Xiaojuan Wen, Xinxiang Wang, Guilei Tian, Chaozhu Shu
Abstract
Abstract Rationally designing efficient catalysts is the key to promote the kinetics of oxygen electrode reactions in lithium‐oxygen (Li‐O 2 ) battery. Herein, nitrogen‐doped Ti 3 C 2 MXene prepared via hydrothermal method (N‐Ti 3 C 2 (H)) is studied as the efficient Li‐O 2 battery catalyst. The nitrogen doping increases the disorder degree of N‐Ti 3 C 2 (H) and provides abundant active sites, which is conducive to the uniform formation and decomposition of discharge product Li 2 O 2 . Besides, density functional theory calculations confirm that the introduction of nitrogen can effectively modulate the 3d orbital occupation of Ti in N‐Ti 3 C 2 (H), promote the electron exchange between Ti 3d orbital and O 2p orbital, and accelerate oxygen electrode reactions. Specifically, the N‐Ti 3 C 2 (H) based Li‐O 2 battery delivers large discharge capacity (11 679.8 mAh g −1 ) and extended stability (372 cycles). This work provides a valuable strategy for regulating 3d orbital occupancy of transition metal in MXene to improve the catalytic activity of oxygen electrode reactions in Li‐O 2 battery.