Fast Li‐ion Conductivity in New Thioborate Halides

October 11, 2021
Fast Li‐ion Conductivity in New Thioborate Halides
Li7.5B10S18I1.5 structure with blue [B10S18 -6] units, lithium (white/green spheres) and iodine (white/purple spheres), where the white shading indicates partial occupancy of that site. The smaller channels contain lithium sites, and the larger channels contain both lithium and iodine sites.

Scientific Achievement

It has been shown that the average structure of halogen substituted electrolyte materials Li7.5B10S18X1.5 (X = Cl, Br, I) exhibits disorder in the Li and X atoms found in large channels, but local order of the X atoms. Combined with weak binding of X to Li ions this permits fast Li-ion conductivity through the channels.

Significance and Impact

Chemical substations in this new class of porous material lead to a promising electrolyte for all-solid-state batteries.

Research Details

  • The ionic conductivities were measured using electrochemical impedance spectroscopy.
  • Detailed crystal structure has been determined with combined single-crystal X-Ray diffraction, neutron diffraction, and neutron pair distribution function (PDF) measurements.
  • Anion disorder was characterized on an average scale using neutron diffraction and at the local scale using neutron PDF.

“Fast Li-Ion Conductivity in Superadamantanoid Lithium Thioborate Halides,”
Kavish Kaup, Abdeljalil Assoud, Jue Liu, and Linda F. Nazar,
Angewandte Chemie International Edition 60, 6975–6980 (2021).