Structure–transport correlations in Na11Sn2SbSe12 and its sulfide solid solutions
Ramos, Erika P.; Assoud, Abdelijalil; Laidong, Zhou; Shyamsunder, Abhinandan; Rettenwander, Daniel; Nazar, Linda F.
Peer reviewed, Journal article
Published version
Permanent lenke
https://hdl.handle.net/11250/3089169Utgivelsesdato
2023Metadata
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- Institutt for materialteknologi [2498]
- Publikasjoner fra CRIStin - NTNU [37221]
Sammendrag
We report a new ion conductor—Na11Sn2SbSe12—as a possible candidate for a solid catholyte in composite cathodes for all-solid state Na-batteries, which exhibits a room temperature ionic conductivity of 0.15 ± 0.03 mS cm−1 and an activation energy of 0.39 ± 0.02 eV. The sulfide solid solutions of Na11Sn2SbSe12, namely, Na11Sn2SbS12−xSex (x = 1 and 6), were also investigated through a combination of Rietveld refinement against powder x-ray diffraction data and electrochemical impedance spectroscopy to reveal the complex structure–property relationships governing ion transport in this class of materials. Meanwhile, broadening of the Na-ion diffusion pathways in Na11Sn2SbSe12 is expected to facilitate Na-ion transport compared to the sulfide-rich member of the solid solution, the opposite holds: increasing the Se fraction in Na11Sn2SbS12−xSex leads to a little change in the activation energy but a reduction in the ionic conductivity. We ascribe this to the lowering of the prefactor, σ0, in the Arrhenius relationship with increasing lattice “softening” as a function of higher Se content.