Atomic pair distribution function research on Li2MnO3 electrode structure evolution

Yubo Yang; Heng Su; Tianhao Wu; Yuyuan Jiang; Danmin Liu; Pengfei Yan; Haolai Tian; Haijun Yu

doi:10.1016/j.scib.2019.03.019

Atomic pair distribution function research on Li₂MnO₃ electrode structure evolution

Sci Bull (Beijing). 2019 Apr 30;64(8):553-561. doi: 10.1016/j.scib.2019.03.019. Epub 2019 Mar 22.

Authors

Yubo Yang¹, Heng Su², Tianhao Wu², Yuyuan Jiang³, Danmin Liu⁴, Pengfei Yan³, Haolai Tian⁵, Haijun Yu⁶

Affiliations

¹ College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing 100124, China; Institute of Solid State Microstructure and Properties, Beijing Key Laboratory of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124, China.
² College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing 100124, China.
³ Institute of Solid State Microstructure and Properties, Beijing Key Laboratory of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124, China.
⁴ Institute of Solid State Microstructure and Properties, Beijing Key Laboratory of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124, China. Electronic address: [email protected].
⁵ China Spallation Neutron Source, Dongguan Institute of Neutron Science, Institute of High Energy of Physics, Chinese Academy of Sciences, Dongguan 523803, China.
⁶ College of Materials Science and Engineering, Key Laboratory of Advanced Functional Materials, Ministry of Education, Beijing University of Technology, Beijing 100124, China. Electronic address: [email protected].

PMID: 36659746
DOI: 10.1016/j.scib.2019.03.019

Abstract

The mechanism research of structure-related reactions on Li₂MnO₃ is important to enhance the electrochemical performance of lithium-manganese-rich layered oxides. Although there are some reports on the structure evolution of Li₂MnO₃ during cycling process, the employed research techniques are very limited, mainly in/ex-situ X-ray diffraction, X-ray absorption and transmission electron microscopy. Here, atomic pair distribution function, a method to study the local atomic arrangement on the basis of average spectroscopic information, is used for the first time to study the local structure evolution of Li₂MnO₃ during electrochemical charge/discharge cycles. The results clearly demonstrate that Mn³⁺/Mn⁴⁺ redox couple is activated and Mn ions are reduced during discharging process. Some Mn ions in Mn layers can significantly migrate to Li layers and occupy the octahedral sites. As a result, a portion of inserted Li ions can occupy the face-shared tetrahedronsites, accompanied by the formation of local spinel-like structure. This work provides an important and suitable method based on the average spectroscopic information to investigate the local structure of electrode materials of lithium-ion batteries as well as other advanced battery systems.

Keywords: Li-ion battery; Lithium-manganese-rich layered oxides; Local structure; Pair distribution function; Structure evolution.