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Manipulating the Local Electronic Structure in Li‐Rich Layered Cathode Towards Superior Electrochemical Performance
Author(s) -
Zheng Hongfei,
Zhang Chenying,
Zhang Yinggan,
Lin Liang,
Liu Pengfei,
Wang Laisen,
Wei Qiulong,
Lin Jie,
Sa Baisheng,
Xie Qingshui,
Peng DongLiang
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202100783
Subject(s) - materials science , faraday efficiency , cathode , electrochemistry , ion , doping , vacancy defect , diffusion , electrode , chemical engineering , activation energy , chemical physics , nanotechnology , chemistry , optoelectronics , crystallography , thermodynamics , physics , quantum mechanics , engineering
Manipulating the local electronic structure is employed to address the capacity/voltage decay and poor rate capability of Li‐rich layered cathodes (LLOs) via the dual‐doping of Na + and F − ions, as well as the regulation of Li + /Ni 2+ intermixing and the content of “LiOLi” configuration. The designed cathode exhibits a high initial Coulombic efficiency of about 90%, large specific capacity of 296 mAh g −1 and energy density of 1047 Wh kg −1 at 0.2 C, and a superior rate capability of 222 mAh g −1 at 5 C with a good capacity retention of 85.7% even after 500 cycles. And the operating voltage is increased without compromising the high‐capacity advantage. Such improved electrochemical performances primarily result from the band shift of the TM 3d‐O 2p and non‐bonding O‐2p to lower energy, which would decrease Li + diffusion activation energy and increase oxygen vacancy forming energy, finally improving the Li + diffusion kinetics and stabilizing lattice oxygen. Moreover, the increased “LiOLi” configuration in the Li 2 MnO 3 phase via increasing the Mn concentration can increase the reversible capacity to offset the negative effect of inactive doping and Li + /Ni 2+ intermixing. This strategy of modulating the local electronic structure of LLOs provides great potential to design high‐energy‐density Li‐ion batteries.