Fast Li-Ion Conductivity in Superadamantanoid Lithium Thioborate Halides

• Published in: Angewandte Chemie (International ed.) Vol. 60; no. 13
• Main Authors: Kaup, Kavish, Assoud, Abdeljalil, Liu, Jue, Nazar, Linda F.
• Format: Journal Article
• Language: English
• Published: United States Wiley 27.11.2020
• Subjects: INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; lithium-ion conductors; neutron diffraction; solid electrolytes; supertetrahedra; thioborate
• ISSN: 1433-7851; 1521-3773

Lithium thioborates are promising fast Li-ion conducting materials, with similar properties to their lithium thiophosphate counterparts that have enabled the development of solid-state Li-ion batteries. By comparison, thioborates have scarcely been developed, however, offering new space for materials discovery. In this work, we report a new class of lithium thioborate halides that adopt a so-called supertetrahedral adamantanoid structure that houses mobile lithium ions and halide anions within interconnected 3D structural channels. Investigation of the structure using single-crystal XRD, neutron powder diffraction, and neutron PDF reveals significant lithium and halide anion disorder. The phases are non-stoichiometric, adopting slightly varying halide contents within the materials. These new superadamantanoid materials exhibit high ionic conductivities up to 1.4 mS cm-1, which can be effectively tuned by the polarizability of the halide anion within the channels.