Li17Sb13S28: A New Lithium Ion Conductor and addition to the Phase Diagram Li2S–Sb2S3. Issue 39 (11th August 2015)

• Record Type: Journal Article
• Authors: Huber, Sebastian; Pfitzner, Arno
• Is Part Of: Chemistry. Volume 21:Issue 39(2015)
• Page Start: 13683
• Page End: 13688
• Publication Date: 2015-08-11
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201502052
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Li<sub>17</sub>Sb<sub>13</sub>S<sub>28</sub> was synthesized by solid‐state reaction of stoichiometric amounts of anhydrous Li<sub>2</sub>S and Sb<sub>2</sub>S<sub>3</sub>. The crystal structure of Li<sub>17</sub>Sb<sub>13</sub>S<sub>28</sub> was determined from dark‐red single crystals at room temperature. The title compound crystallizes in the monoclinic space group <italic>C</italic>2<italic>/m</italic> (no. 12) with <italic>a</italic>=12.765(2) Å, <italic>b</italic>=11.6195(8) Å, <italic>c</italic>=9.2564(9) Å, <italic>β</italic>=119.665(6)°, <italic>V</italic>=1193.0(2) Å<sup>3</sup>, and <italic>Z</italic>=4 (data at 20 °C, lattice constants from powder diffraction). The crystal structure contains one cation site with a mixed occupation by Li and Sb, and one with an antimony split position. Antimony and sulfur form slightly distorted tetragonal bipyramidal [SbS<sub>5</sub><italic>E</italic>] units (<italic>E</italic>=free electron pair). Six of these units are arranged around a vacancy in the anion substructure. The lone electron pairs <italic>E</italic> of the antimony(<sc>III)</sc> cations are arranged around these vacancies. Thus, a variant of the rock salt structure type with ordered vacancies in the anionic substructure results. Impedance spectroscopic measurements of Li<sub>17</sub>Sb<sub>13</sub>S<sub>28</sub> show a specific conductivity of 2.9×10<sup>−9</sup> Ω<sup>−1</sup> cm<sup>−1</sup> at 323 K and of 7.9×10<sup>−6</sup> Ω<sup>−1</sup> cm<sup>−1</sup> at 563 K, the corresponding activation energy is <italic>E</italic><sub>A</sub>=0.4 eV below 403 K and <italic>E<sub>A</sub></italic>=0.6 eV above. Raman spectra are dominated by the SbS stretching modes of the [SbS<sub>5</sub>] units at 315 and 341 cm<sup>−1</sup> at room temperature. Differential thermal analysis (DTA) measurements of Li<sub>17</sub>Sb<sub>13</sub>S<sub>28</sub> indicate peritectic melting at 854 K.</p> </abstract>