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oai:figshare.com:article/34042334 2026-10-01T10:03:26Z category_1 category_4 category_873 category_734 portal_63 item_type_6 month_year_10_2026

Halide-Driven Stabilization of a Hexagonal Polymorph with a Distinct and Disordered Li Substructure in Li_3.25GeS_3.25Cl_0.75 Hyeonjin Seo (24710381) Alicia Manjón-Sanz (1952074) Seung-Tae Hong (2442292) Biophysics Biochemistry Chemical Sciences not elsewhere classified Biological Sciences not elsewhere classified temperature ionic conductivity sulfide solid electrolytes preferentially stabilized near packed anion framework octahedral interstitial sites average structure built 91 × 10 structural analysis indicates access structural motifs secondary crystalline phase 2 –</ sup stabilize hexagonal polymorphs calculated percolation topology sup >–</ sup resulting framework exhibits hexagonal polymorph near inequivalent li environments ge occupational disorder 25 </ sub halide substitution produces disordered li substructure 75 </ sub 4 </ sub structural disorder hexagonal polymorph hexagonal phase 75 composition p </ mc </ 4 –< x </ hexagonal close site topology partial substitution halide substitution energy topology li substructure systematic investigation series shows Targeted halide substitution provides an effective route to access structural motifs in thio-LISICON systems. Here, partial substitution of S^2– by Cl^– in Li₄GeS₄ stabilizes a hexagonal polymorph near the composition Li_3.25GeS_3.25Cl_0.75. Ab initio structure determination by joint refinement of time-of-flight neutron powder diffraction and X-ray diffraction data supports a <i>P</i>6₃<i>mc</i> average structure built on a hexagonal close-packed anion framework. The resulting framework exhibits a distinct Li-site topology with symmetry-inequivalent Li environments, including a shared tetrahedral framework site and additional tetrahedral and octahedral interstitial sites. Systematic investigation of the Li_4–<i>x</i>GeS_4–<i>x</i>Cl_<i>x</i> series shows that the hexagonal phase is preferentially stabilized near the nominal <i>x</i> = 0.75 composition, for which no secondary crystalline phase was detected by PXRD. Structural analysis indicates that halide substitution produces a rearranged and partially disordered Li substructure. Bond-valence energy landscape calculations show that the computed Li-energy topology is highly sensitive to the representation of Li/Ge occupational disorder, with a Ge-free sensitivity model recovering the crystallographic Li1-related minimum and markedly altering the calculated percolation topology. Li_3.25GeS_3.25Cl_0.75 exhibits a room-temperature ionic conductivity of 3.91 × 10^–6 S cm^–1. These results demonstrate that halide substitution can stabilize hexagonal polymorphs and reorganize the Li substructure in sulfide solid electrolytes, providing a platform for examining how structural disorder and Li-site topology influence ion transport. 2026-10-01T00:00:00Z Text Journal contribution 10.1021/acs.chemmater.6c01317.s001 https://figshare.com/articles/journal_contribution/Halide-Driven_Stabilization_of_a_Hexagonal_Polymorph_with_a_Distinct_and_Disordered_Li_Substructure_in_Li_sub_3_25_sub_GeS_sub_3_25_sub_Cl_sub_0_75_sub_/34042334 CC BY-NC 4.0