%0 Journal Article
%A Schuett, Judith
%A Schillings, Johanna
%A Neitzel-Grieshammer, Steffen
%T Interstitial or interstitialcy: effect of the cation size on the migration mechanism in NaSICON materials
%J Physical chemistry, chemical physics
%V 26
%N 3
%@ 1463-9076
%C Cambridge
%I RSC Publ.
%M FZJ-2024-02612
%P 2190 - 2204
%D 2024
%X Sodium superionic conductors (NaSICONs) with general formula NaM2A3O12 have attracted significant attention as solid electrolytes for all solid-state batteries owing to their remarkable room temperature ionic conductivity in the order of 10−3 S cm−1. Their flexible structural framework, which allows the incorporation of various aliovalent cations, affects the Na+ ion transport. However, establishing a straightforward correlation between Na+ mobility and NaSICON composition proves challenging due to competing influences such as framework alteration and stoichiometric changes of the cation substituents and thus the mobile Na+ ions. Therefore, we systematically investigate the NaSICON system across various Na1+xM2SixP3−xO12 compositions. We unravel and examine independently two key aspects impacting the Na+ ion transport in NaSICONs: structural factors determined by introduced M4+ framework cations and the substitution level (x). By employing DFT calculations, we explore the interstitial- and interstitialcy-like migration mechanisms, revealing that these mechanisms and the associated migration energies are primarily influenced by metastable transient states traversed during the Na+ ion migration. The stability of these transient states, in turn, depends on the spatial arrangement of the Na+ ions, the size of the M4+ cations defining the structural framework, and x. This study enhances our fundamental understanding of Na+ ion migration within NaSICONs across a wide range of compositions. The findings offer valuable insights into the microscopic aspects of NaSICON materials and provide essential guidance for prospective studies in this field.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ 38164803
%U <Go to ISI:>//WOS:001134532100001
%R 10.1039/D3CP05089K
%U https://juser.fz-juelich.de/record/1025018