Structure–transport correlations in Na11Sn2SbSe12 and its sulfide solid solutions

Journal article

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.publishedVersio

Authors: Ramos, EP; Assoud, A; Zhou, L; Shyamsunder, A; Rettenwander, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Institute of Physics
• Journal: APL Materials
• Volume: 11
• Issue: 1
• Pages: 011104
• Article number: 011104
• Publication date: 2023-01-23
• DOI: 10.1063/5.0129001
• EISSN: 2166-532X
• ISSN: 2166-532X
• Language: English
• Keywords: Solid solution; Analytical Chemistry (journal); Arrhenius equation; Electrochemistry; Ionic bonding; Crystallography; Crystal structure; Chemistry; Ion; Materials science; Electrode; Inorganic chemistry; Activation energy; Dielectric spectroscopy; Ionic conductivity; Physical chemistry; Sulfide; Metallurgy; Rietveld refinement; Conductivity