Surface Design with Cation and Anion Dual Gradient Stabilizes High‐Voltage LiCoO 2

Abstract LiCoO 2 (LCO) is the most successful cathode material for commercial lithium‐ion batteries. Cycling LCO to high potentials up to 4.5 V or even 4.6 V can significantly elevate the capacity but cause structural degradation due to the serious surface side reaction between the highly oxidized C...

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Bibliographic Details
Published in:Advanced energy materials 2022-05, Vol.12 (20)
Main Authors: Huang, Weiyuan, Zhao, Qi, Zhang, Mingjian, Xu, Shenyang, Xue, Haoyu, Zhu, Chen, Fang, Jianjun, Zhao, Wenguang, Ren, Guoxi, Qin, Runzhi, Zhao, Qinghe, Chen, Haibiao, Pan, Feng
Format: Article
Language:English
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Summary:Abstract LiCoO 2 (LCO) is the most successful cathode material for commercial lithium‐ion batteries. Cycling LCO to high potentials up to 4.5 V or even 4.6 V can significantly elevate the capacity but cause structural degradation due to the serious surface side reaction between the highly oxidized Co 4+ and O − species with organic electrolytes. To tackle this concern, a new strategy, constructing cation and anion dual gradients at the surface of LCO (DG‐LCO), is proposed. Specifically, the electrochemically inactive cation and anion are selected to substitute Co 3+ and O 2− at the surface in a gradated manner, thus minimizing the highly oxidized Co 4+ and O − species at high potentials and suppressing the induced surface side reactions. Unexpectedly, this dual gradient design leads to a spinel‐like surface structure coherently with bulk layered structure, which facilitates Li + diffusion kinetics. Thus, DG‐LCO achieves high capacity and excellent cycling stability at 4.6 V (≈216 mA h g −1 at 0.1 C, a capacity retention of 88.6% after 100 cycles in 1.8 A h pouch full cell at 1 C), as well as improved rate capability (≈140 mA h g −1 at 5 C). These studies provide useful guidelines for future design of cathode materials with long lifespan and high rate capability.
ISSN:1614-6832
1614-6840
DOI:10.1002/aenm.202200813