Journal Article

FZJ-2023-02065

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png On the Discrepancy between Local and Average Structure in the Fast $Na^+$ Ionic Conductor $Na_{2.9}Sb_{0.9}W_{0.1}S_{4}$

Maus, O. ; Agne, M. T. ; Fuchs, T. ; Till, P. S. ; Wankmiller, B. ; Gerdes, J. M. ; Sharma, R. ; Heere, M. ; Jalarvo, N. ; Yaffe, O. ; Hansen, M. R. ; Zeier, W. G. (Corresponding author)FZJ*

2023
ACS Publications Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/34443  doi:10.1021/jacs.2c11803

Abstract: Aliovalent substitution is a common strategy to improve the ionic conductivity of solid electrolytes for solid-state batteries. The substitution of SbS43– by WS42– in Na2.9Sb0.9W0.1S4 leads to a very high ionic conductivity of 41 mS cm–1 at room temperature. While pristine Na3SbS4 crystallizes in a tetragonal structure, the substituted Na2.9Sb0.9W0.1S4 crystallizes in a cubic phase at room temperature based on its X-ray diffractogram. Here, we show by performing pair distribution function analyses and static single-pulse 121Sb NMR experiments that the short-range order of Na2.9Sb0.9W0.1S4 remains tetragonal despite the change in the Bragg diffraction pattern. Temperature-dependent Raman spectroscopy revealed that changed lattice dynamics due to the increased disorder in the Na+ substructure leads to dynamic sampling causing the discrepancy in local and average structure. While showing no differences in the local structure, compared to pristine Na3SbS4, quasi-elastic neutron scattering and solid-state 23Na nuclear magnetic resonance measurements revealed drastically improved Na+ diffusivity and decreased activation energies for Na2.9Sb0.9W0.1S4. The obtained diffusion coefficients are in very good agreement with theoretical values and long-range transport measured by impedance spectroscopy. This work demonstrates the importance of studying the local structure of ionic conductors to fully understand their transport mechanisms, a prerequisite for the development of faster ionic conductors.

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Contributing Institute(s):

1. Helmholtz-Institut Münster Ionenleiter für Energiespeicher (IEK-12)

Research Program(s):

1. 1221 - Fundamentals and Materials (POF4-122) (POF4-122)

Appears in the scientific report 2023

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Database coverage:
; ; BIOSIS Previews ; Clarivate Analytics Master Journal List ; Current Contents - Life Sciences ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF >= 10 ; JCR ; Nationallizenz ; SCOPUS ; Web of Science Core Collection

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