Abstract Localized atomistic disorder in halide‐based solid electrolytes (SEs) can be leveraged to boost Li+mobility. In this study, Li+transport in structurally modified Li3HoCl6, via Br−introduction and Li+deficiency, is explored. The optimized Li3‐3yHo1+yCl6‐xBrxachieves an ionic conductivity of 3.8 mS cm−1at 25 °C, the highest reported for holmium halide materials.6,7Li nuclear magnetic resonance and relaxometry investigations unveil enhanced ion dynamics with bromination, attaining a Li+motional rate neighboring 116 MHz. X‐ray diffraction analyses reveal mixed‐anion‐induced phase transitions with disproportionate octahedral expansions and distortions, creating Ho‐free planes with favorable energetics for Li+migration. Bond valence site energy analysis highlights preferred Li+transport pathways, particularly in structural planes devoid of Ho3+blocking effects. Molecular dynamics simulations corroborate enhanced Li+diffusion with Br−introduction into Li3HoCl6. Li‐Ho electrostatic repulsions in the (001) plane presumably drive Li+diffusion into the Ho‐free (002) layer, enabling rapid intraplanar Li+motion and exchange between the 2d and 4h sites. Li3‐3yHo1+yCl6‐xBrxalso demonstrates good battery cycling stability. These findings offer valuable insights into the intricate correlations between structure and ion transport and will help guide the design of high‐performance fast ion conductors for all‐solid‐state batteries.
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Electronic stabilization by occupational disorder in the ternary bismuthide Li 3–x–y In x Bi ( x ≃ 0.14, y ≃ 0.29)
A ternary derivative of Li 3 Bi with the composition Li 3– x – y In x Bi ( x ≃ 0.14, y ≃ 0.29) was produced by a mixed In+Bi flux approach. The crystal structure adopts the space group Fd \overline{3} m (No. 227), with a = 13.337 (4) Å, and can be viewed as a 2 × 2 × 2 superstructure of the parent Li 3 Bi phase, resulting from a partial ordering of Li and In in the tetrahedral voids of the Bi fcc packing. In addition to the Li/In substitutional disorder, partial occupation of some Li sites is observed. The Li deficiency develops to reduce the total electron count in the system, counteracting thereby the electron doping introduced by the In substitution. First-principles calculations confirm the electronic rationale of the observed disorder.
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- Award ID(s):
- 1709813
- PAR ID:
- 10208971
- Date Published:
- Journal Name:
- Acta Crystallographica Section C Structural Chemistry
- Volume:
- 76
- Issue:
- 6
- ISSN:
- 2053-2296
- Page Range / eLocation ID:
- 585 to 590
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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