中国物理B ›› 2021, Vol. 30 ›› Issue (7): 78202-078202.doi: 10.1088/1674-1056/abf347

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Electron density distribution of LiMn2O4 cathode investigated by synchrotron powder x-ray diffraction

Tongtong Shang(尚彤彤)1,2, Dongdong Xiao(肖东东)1,3,†, Qinghua Zhang(张庆华)1,4,‡, Xuefeng Wang(王雪锋)1,2, Dong Su(苏东)1,2, and Lin Gu(谷林)1,2,3,§   

  1. 1 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    2 School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;
    3 Songshan Lake Materials Laboratory, Dongguan 523808, China;
    4 Yangtze River Delta Physics Research Center Co. Ltd., Liyang 213300, China
  • 收稿日期:2021-03-03 修回日期:2021-03-22 接受日期:2021-03-30 出版日期:2021-06-22 发布日期:2021-07-02
  • 通讯作者: Dongdong Xiao, Qinghua Zhang, Lin Gu E-mail:dongdongxiao@iphy.ac.cn;zqh@iphy.ac.cn;l.gu@iphy.ac.cn
  • 基金资助:
    Project supported by Beijing Natural Science Foundation, China (Grant No. Z190010), the National Key Research and Development Program of China (Grant No. 2019YFA0308500), the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB07030200), Key Research Projects of Frontier Science of Chinese Academy of Sciences (Grant No. QYZDB-SSW-JSC035), and the National Natural Science Foundation of China (Grant Nos. 51421002, 51672307, 51991344, 52025025, and 52072400).

Electron density distribution of LiMn2O4 cathode investigated by synchrotron powder x-ray diffraction

Tongtong Shang(尚彤彤)1,2, Dongdong Xiao(肖东东)1,3,†, Qinghua Zhang(张庆华)1,4,‡, Xuefeng Wang(王雪锋)1,2, Dong Su(苏东)1,2, and Lin Gu(谷林)1,2,3,§   

  1. 1 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
    2 School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;
    3 Songshan Lake Materials Laboratory, Dongguan 523808, China;
    4 Yangtze River Delta Physics Research Center Co. Ltd., Liyang 213300, China
  • Received:2021-03-03 Revised:2021-03-22 Accepted:2021-03-30 Online:2021-06-22 Published:2021-07-02
  • Contact: Dongdong Xiao, Qinghua Zhang, Lin Gu E-mail:dongdongxiao@iphy.ac.cn;zqh@iphy.ac.cn;l.gu@iphy.ac.cn
  • Supported by:
    Project supported by Beijing Natural Science Foundation, China (Grant No. Z190010), the National Key Research and Development Program of China (Grant No. 2019YFA0308500), the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB07030200), Key Research Projects of Frontier Science of Chinese Academy of Sciences (Grant No. QYZDB-SSW-JSC035), and the National Natural Science Foundation of China (Grant Nos. 51421002, 51672307, 51991344, 52025025, and 52072400).

摘要: Electron density plays an important role in determining the properties of functional materials. Revealing the electron density distribution experimentally in real space can help to tune the properties of materials. Spinel LiMn2O4 is one of the most promising cathode candidates because of its high voltage, low cost, and non-toxicity, but suffers severe capacity fading during electrochemical cycling due to the Mn dissolution. Real-space measurement of electron distribution of LiMn2O4 experimentally can provide direct evaluation on the strength of Mn-O bond and give an explanation of the structure stability. Here, through high energy synchrotron powder x-ray diffraction (SPXRD), accurate electron density distribution in spinel LiMn2O4 has been investigated based on the multipole model. The electron accumulation between Mn and O atoms in deformation density map indicates the shared interaction of Mn-O bond. The quantitative topological analysis at bond critical points shows that the Mn-O bond is relatively weak covalent interaction due to the oxygen loss. These findings suggest that oxygen stoichiometry is the key factor for preventing the Mn dissolution and capacity fading.

关键词: lithium-ion batteries, LiMn2O4, electron density distribution

Abstract: Electron density plays an important role in determining the properties of functional materials. Revealing the electron density distribution experimentally in real space can help to tune the properties of materials. Spinel LiMn2O4 is one of the most promising cathode candidates because of its high voltage, low cost, and non-toxicity, but suffers severe capacity fading during electrochemical cycling due to the Mn dissolution. Real-space measurement of electron distribution of LiMn2O4 experimentally can provide direct evaluation on the strength of Mn-O bond and give an explanation of the structure stability. Here, through high energy synchrotron powder x-ray diffraction (SPXRD), accurate electron density distribution in spinel LiMn2O4 has been investigated based on the multipole model. The electron accumulation between Mn and O atoms in deformation density map indicates the shared interaction of Mn-O bond. The quantitative topological analysis at bond critical points shows that the Mn-O bond is relatively weak covalent interaction due to the oxygen loss. These findings suggest that oxygen stoichiometry is the key factor for preventing the Mn dissolution and capacity fading.

Key words: lithium-ion batteries, LiMn2O4, electron density distribution

中图分类号:  (Lithium-ion batteries)

  • 82.47.Aa
82.45.Fk (Electrodes) 71.20.-b (Electron density of states and band structure of crystalline solids)