Manipulating the Local Electronic Structure in Li‐Rich Layered Cathode Towards Superior Electrochemical Performance. (16th May 2021)

• Record Type: Journal Article
• Authors: Zheng, Hongfei; Zhang, Chenying; Zhang, Yinggan; Lin, Liang; Liu, Pengfei; Wang, Laisen; Wei, Qiulong; Lin, Jie; Sa, Baisheng; Xie, Qingshui; Peng, Dong‐Liang
• Is Part Of: Advanced functional materials. Volume 31:Number 30(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-05-16
• Subjects: cycling stability -- dual doping -- electronic structure modulation -- Li‐rich layered cathodes -- operating voltage; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202100783
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: 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 "LiOLi" 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 "LiOLi" configuration in the Li2 MnO3 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. Abstract : The local electronic structure is modulated effectively via adjusting the local atomic coordination, triggering the TM 3d‐O 2p bands and non‐bonding O‐2p bands to lower energy. The low‐energy shift quickens the Li + diffusion kinetics and stabilizes the lattice oxygen. As a result, outstanding electrochemical performance is achieved.