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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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Tetrahedral Tilting and Lithium‐Ion Transport in Halide Argyrodites Prepared by Rapid, Microwave‐Assisted Synthesis
Abstract This study demonstrates a rapid, dry, microwave‐assisted (MW) synthesis method that enables preparation of halide argyrodites ( , , ) in less than 20 min. The structures and ion transport properties of the resulting materials are compared with those synthesized by conventional solid‐state synthesis methods. The microwave‐assisted method leads to increased site disorder and elevated Arrhenius prefactors (), which lead to an order of magnitude improvement in the 30 ionic conductivity of MW‐. X‐ray pair distribution function analysis (XPDF) reveals significant rotational disorder of the units, which is impacted by the synthesis method, choice of halide, and presence of / site disorder. These rotational displacements are strongly correlated with ion transport, specifically and entropy of migration (). Overall, this study demonstrates a rapid synthesis route for preparing high‐quality halide argyrodite solid‐state electrolytes in less than 20 min, and further unravels atomistic insights into the interplay of structural disorder, rotational dynamics, and ion transport mechanisms.
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- Award ID(s):
- 2244331
- PAR ID:
- 10571564
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 35
- Issue:
- 23
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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