Abstract

Layered oxide NaxMO2 (M: transition metal) is a promising cathode material for sodium-ion secondary battery. Crystal structure of O3- and P2-type NaxMO2 with various M against temperature (T) was systematically investigated by synchrotron x-ray diffraction mainly focusing on the T-dependences of a- and c-axis lattice constants (a and c) and z coordinate (z) of oxygen. Using a hard-sphere model with minimum Madelung energy, we confirmed that c/a and z values in O3-type NaxMO2 were reproduced. We further evaluated the thermal expansion coefficients (αa and αc) along a- and c-axis at 300 K. The anisotropy of the thermal expansion was quantitatively reproduced without adjustable parameters for O3-type NaxMO2. Deviations of z from the model for P2-type NaxMO2 are ascribed to Na vacancies characteristic to the structure.

Details

Title
Thermal Expansion in Layered Na x MO2
Author
Kobayashi, Wataru 1 ; Yanagita, Ayumu 2 ; Akaba, Takahiro 2 ; Shimono, Takahiro 2 ; Tanabe, Daiki 2 ; Moritomo, Yutaka 1   VIAFID ORCID Logo 

1  Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki, Japan; Division of Physics, Faculty of Pure and Applied Sciences, University of Tsukuba, Ibaraki, Japan; Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba, Ibaraki, Japan 
2  Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki, Japan 
Pages
1-9
Publication year
2018
Publication date
Mar 2018
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1038/s41598-018-22279-9
ProQuest document ID
2010823909
Copyright
© 2018. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.