Journal Article

FZJ-2026-00027

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Insight into the prospects and limitations of mechanochemically-synthesised lithium tetrahalogallates, $LiGaX_4 (X = Cl, Br, I)$, as Li-ion conductors

Flores-González, N. ; López, M. ; Minafra, N. ; Jack, J. ; Bohnenberger, J. ; Inoishi, A. ; Gupta, N. ; Liborio, L. ; Viñes, F. ; Smith, R. I. ; Baker, P. J. ; Krossing, I. ; Zeier, W. G.FZJ* ; Illas, F. ; Gregory, D. H. (Corresponding author)

2025
RSC Cambridge

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Please use a persistent id in citations: doi:10.1039/D5SC03999A  doi:10.34734/FZJ-2026-00027

Abstract: Halide solid-state electrolytes have attracted significant interest due to their appreciable $Li^+$ conductivity at room temperature, good electrochemical stability against oxidation, and favourable compatibility with oxide cathodes. Nevertheless, the family of lithium tetrahalogallates, $LiGaX_4 (X = Cl, Br, I)$, has scarcely been studied and, consequently, their physicochemical properties remained largely unknown. In this work, we report the mechanochemical synthesis of high-purity $LiGaX_4$ and investigate their crystal structures, thermal, electronic, vibrational, and ionic transport properties through a combination of advanced characterisation techniques and computational methods. Powder X-ray and neutron diffraction confirm that all three phases crystallise in a monoclinic unit cell (P21/c), isostructural to LiAlX4 analogues. Preliminary results indicate that $LiGaBr_4$ exhibits the highest ionic conductivity at room temperature (4.87 $× 10^{−6} S cm^{−1}$) among the series. Compared to $LiAlX_4$, the diffusion pathways in $LiGaX_4$ showed a lower dimensionality and higher activation energies for $Li^+$ diffusion, which results in reduced ionic conductivities. Periodic density functional theory (DFT) based calculations indicate a general correlation between computed band gaps and electrochemical windows in $LiMX_4$ materials ($M = Al, Ga; X = Cl, Br, I$). Additionally, $μ^+$SR data demonstrate that softer lattices provide lower activation energies for $Li^+$ migration and suggest that additional factors influence the results obtained through electrochemical impedance spectroscopy.

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Contributing Institute(s):

1. Helmholtz-Institut Münster Ionenleiter für Energiespeicher (IMD-4)

Research Program(s):

1. 1221 - Fundamentals and Materials (POF4-122) (POF4-122)

Appears in the scientific report 2025

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Database coverage:
; ; ; ; Chemical Reactions ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; Essential Science Indicators ; IF >= 5 ; Index Chemicus ; JCR ; National-Konsortium ; PubMed Central ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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