Restraining Oxygen Release and Suppressing Structure Distortion in Single‐Crystal Li‐Rich Layered Cathode Materials

Li‐rich oxides can be regarded as the next‐generation cathode materials for high‐energy‐density Li‐ion batteries since additional oxygen redox activities greatly increase output energy density. However, the oxygen loss and structural distortion induce low initial coulombic efficiency and severe deca...

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Bibliographic Details
Published in:Advanced functional materials 2022-03, Vol.32 (10), p.n/a
Main Authors: Sun, Jianming, Sheng, Chuanchao, Cao, Xin, Wang, Pengfei, He, Ping, Yang, Huijun, Chang, Zhi, Yue, Xiyan, Zhou, Haoshen
Format: Article
Language:English
Subjects:
Cathodes
Crystal morphology
Crystal structure
cycle performance
Cycles
Distortion
Electrode materials
Flux density
Industrial applications
Lithium-ion batteries
Li‐rich cathode materials
Materials science
Morphology
Oxygen
oxygen release
Phase transitions
Polycrystals
Rechargeable batteries
Redox reactions
Single crystals
single‐crystal
Structural stability
structure distortion
Superlattices
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Summary:Li‐rich oxides can be regarded as the next‐generation cathode materials for high‐energy‐density Li‐ion batteries since additional oxygen redox activities greatly increase output energy density. However, the oxygen loss and structural distortion induce low initial coulombic efficiency and severe decay of cycle performance, further hindering their industrial applications. Herein, the representative layered Li‐rich cathode material, Li1.2Ni0.2Mn0.6O2, is endowed with novel single‐crystal morphology. In comparison to its polycrystal counterpart, not only can serious oxygen release be effectively restrained during the first oxygen activation process, but also the layered/spinel phase transition can be well suppressed upon cycling. Moreover, the single‐crystal cathode exhibits the limited volume change and persistent presence of superlattice peaks upon Li+ (de)intercalation processes, resulting in enhanced structural stability with absence of crack generation and successive utilization of oxygen redox reaction during long‐term cycling. Benefiting from these unique features, the single‐crystal Li‐rich electrode not only yields a high reversible capacity of 257 mAh g−1, but also achieves excellent cycling performance with 92% capacity retention after 200 cycles. These findings demonstrate that the morphology design of single crystals can be regarded as an effective strategy to realize high‐energy density and long‐life Li‐ion batteries. The electrochemical behaviors, structural evolution, and oxygen activities of polycrystal and single‐crystal Li‐rich electrodes are comprehensively compared, which effectively demonstrate that the morphology design of single crystals can be regarded as an effective strategy to realize next‐generation high‐energy‐density Li‐ion batteries.
ISSN:1616-301X
1616-3028
DOI:10.1002/adfm.202110295