Abstract
We report a new fast ion-conducting lithium thioborate halide, Li6B7S13I, that crystallizes in either a cubic or tetragonal thioboracite structure, which is unprecedented in boron-sulfur chemistry. The cubic phase exhibits a perovskite topology and an argyrodite-like lithium substructure that leads to superionic conduction with a theoretical Li-ion conductivity of 5.2 mS cm-1 calculated from ab initio molecular dynamics (AIMD). Combined single-crystal X-ray diffraction, neutron powder diffraction, and AIMD simulations elucidate the Li+-ion conduction pathways through 3D intra- and intercage connections and Li-ion site disorder, which are all essential for high lithium mobility. Furthermore, we demonstrate that Li+ ordering in the tetragonal polymorph impedes lithium-ion conduction, thus highlighting the importance of the lithium substructure and lattice symmetry in dictating transport properties.
| Original language | English |
|---|---|
| Pages (from-to) | 6952-6961 |
| Number of pages | 10 |
| Journal | Journal of the American Chemical Society |
| Volume | 143 |
| Issue number | 18 |
| DOIs | |
| State | Published - May 12 2021 |
Funding
This research was supported by the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences. L.F.N. is also grateful to the Natural Sciences and Engineering Research Council of Canada (NSERC) for funding via their Discovery Grant and Canada Research Chair programs, and K.K. kindly acknowledges funding from a CGS-D doctoral graduate scholarship. Neutron powder diffraction measurements on POWGEN employed resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The theoretical calculations were performed on the Shared Hierarchical Academic Research Computing Network (SHARCNET: www.sharcnet.ca ) and Compute Canada. We thank Prof. P. N. Roy for use of his supercomputing cluster in the initial stages of the DFT calculations.