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Voltage decay and redox asymmetry mitigation by reversible cation migration in lithium-rich layered oxide electrodes

Cited 58 time in Web of Science Cited 69 time in Scopus
Authors
Eum, Donggun; Kim, Byunghoon; Kim, Sung Joo; Park, Hyeokjun; Wu, Jinpeng; Cho, Sung-Pyo; Yoon, Gabin; Lee, Myeong Hwan; Jung, Sung-Kyun; Yang, Wanli; Seong, Won Mo; Ku, Kyojin; Tamwattana, Orapa; Park, Sung Kwan; Hwang, Insang; Kang, Kisuk
Issue Date
2020-04
Citation
Nature Materials, Vol.19 No.4, pp.419-427
Abstract
The use of high-energy-density lithium-rich layered-oxide electrodes in batteries is hindered by voltage decay on cycling. Improving the reversible cation migration by altering oxygen stacking is shown to suppress voltage decay and redox asymmetry in lithium-rich nickel manganese oxides. Despite the high energy density of lithium-rich layered-oxide electrodes, their real-world implementation in batteries is hindered by the substantial voltage decay on cycling. This voltage decay is widely accepted to mainly originate from progressive structural rearrangements involving irreversible transition-metal migration. As prevention of this spontaneous cation migration has proven difficult, a paradigm shift toward management of its reversibility is needed. Herein, we demonstrate that the reversibility of the cation migration of lithium-rich nickel manganese oxides can be remarkably improved by altering the oxygen stacking sequences in the layered structure and thereby dramatically reducing the voltage decay. The preeminent intra-cycle reversibility of the cation migration is experimentally visualized, and first-principles calculations reveal that an O2-type structure restricts the movements of transition metals within the Li layer, which effectively streamlines the returning migration path of the transition metals. Furthermore, we propose that the enhanced reversibility mitigates the asymmetry of the anionic redox in conventional lithium-rich electrodes, promoting the high-potential anionic reduction, thereby reducing the subsequent voltage hysteresis. Our findings demonstrate that regulating the reversibility of the cation migration is a practical strategy to reduce voltage decay and hysteresis in lithium-rich layered materials.
ISSN
1476-1122
URI
https://hdl.handle.net/10371/171793
DOI
https://doi.org/10.1038/s41563-019-0572-4
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College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Material Science and Engineering (재료공학부) Journal Papers (저널논문_재료공학부)
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