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Chemical and structural evolutions of Li-Mn-rich layered electrodes at different current densities

He, Xin ; Wu, Jue ; Zhu, Zhuoying ; Liu, Haodong ; Li, Ning ; Zhou, Dong ; Hou, Xu LU orcid ; Wang, Jun ; Zhang, Haowei and Bresser, Dominic , et al. (2022) In Energy and Environmental Science 15(10). p.4137-4147
Abstract

Although the two active redox centers in Li-rich cathodes, including the anionic and cationic contributions, can enable Li-ion batteries to achieve outstanding specific energy, their behaviors at different current densities have not been clarified. Here, we provide a comparative study of transition metals (TMs) and oxygen redox activities by directly accessing their oxidation states in Li-rich materials operated at very different current rates. Our data reveal that the oxidation of oxygen in the near-surface region is at the same level for electrodes cycled with a wide range of current rates, indicating a reaction gradient of lattice oxygen redox reactions. The oxidation process of lattice oxygen is found to be dynamically compatible... (More)

Although the two active redox centers in Li-rich cathodes, including the anionic and cationic contributions, can enable Li-ion batteries to achieve outstanding specific energy, their behaviors at different current densities have not been clarified. Here, we provide a comparative study of transition metals (TMs) and oxygen redox activities by directly accessing their oxidation states in Li-rich materials operated at very different current rates. Our data reveal that the oxidation of oxygen in the near-surface region is at the same level for electrodes cycled with a wide range of current rates, indicating a reaction gradient of lattice oxygen redox reactions. The oxidation process of lattice oxygen is found to be dynamically compatible with that of the TMs. Combining the results of first principles calculations and complementary experimental findings, we propose a detailed mechanism of structural distortion from octahedral Li to tetrahedral Li and the role of oxygen vacancy in Li+ diffusion. It is found that fast delithiation occurring at high current densities can easily cause local structural transformation, leading to a limited Li+ diffusion rate and consequently suppressing rate capability.

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publishing date
type
Contribution to journal
publication status
published
in
Energy and Environmental Science
volume
15
issue
10
pages
11 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85137997168
ISSN
1754-5692
DOI
10.1039/d2ee01229d
language
English
LU publication?
no
additional info
Publisher Copyright: © 2022 The Royal Society of Chemistry.
id
f7f12b65-0e10-4604-98aa-70582d826ed5
date added to LUP
2025-12-05 22:32:00
date last changed
2025-12-11 14:37:50
@article{f7f12b65-0e10-4604-98aa-70582d826ed5,
  abstract     = {{<p>Although the two active redox centers in Li-rich cathodes, including the anionic and cationic contributions, can enable Li-ion batteries to achieve outstanding specific energy, their behaviors at different current densities have not been clarified. Here, we provide a comparative study of transition metals (TMs) and oxygen redox activities by directly accessing their oxidation states in Li-rich materials operated at very different current rates. Our data reveal that the oxidation of oxygen in the near-surface region is at the same level for electrodes cycled with a wide range of current rates, indicating a reaction gradient of lattice oxygen redox reactions. The oxidation process of lattice oxygen is found to be dynamically compatible with that of the TMs. Combining the results of first principles calculations and complementary experimental findings, we propose a detailed mechanism of structural distortion from octahedral Li to tetrahedral Li and the role of oxygen vacancy in Li<sup>+</sup> diffusion. It is found that fast delithiation occurring at high current densities can easily cause local structural transformation, leading to a limited Li<sup>+</sup> diffusion rate and consequently suppressing rate capability.</p>}},
  author       = {{He, Xin and Wu, Jue and Zhu, Zhuoying and Liu, Haodong and Li, Ning and Zhou, Dong and Hou, Xu and Wang, Jun and Zhang, Haowei and Bresser, Dominic and Fu, Yanbao and Crafton, Matthew J. and McCloskey, Bryan D. and Chen, Yan and An, Ke and Liu, Ping and Jain, Anubhav and Li, Jie and Yang, Wanli and Yang, Yong and Winter, Martin and Kostecki, Robert}},
  issn         = {{1754-5692}},
  language     = {{eng}},
  month        = {{07}},
  number       = {{10}},
  pages        = {{4137--4147}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Energy and Environmental Science}},
  title        = {{Chemical and structural evolutions of Li-Mn-rich layered electrodes at different current densities}},
  url          = {{http://dx.doi.org/10.1039/d2ee01229d}},
  doi          = {{10.1039/d2ee01229d}},
  volume       = {{15}},
  year         = {{2022}},
}