Thermal Expansion in Layered Na x MO2.
Sci Rep
; 8(1): 3988, 2018 Mar 05.
Article
em En
| MEDLINE
| ID: mdl-29507326
ABSTRACT
Layered oxide Na x MO2 (M transition metal) is a promising cathode material for sodium-ion secondary battery. Crystal structure of O3- and P2-type Na x MO2 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 Na x MO2 were reproduced. We further evaluated the thermal expansion coefficients (α a and α c ) along a- and c-axis at 300 K. The anisotropy of the thermal expansion was quantitatively reproduced without adjustable parameters for O3-type Na x MO2. Deviations of z from the model for P2-type Na x MO2 are ascribed to Na vacancies characteristic to the structure.
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1
Base de dados:
MEDLINE
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Sci Rep
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Japão