Journal Article

FZJ-2026-00026

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Electrochemical Performance and Stability of $Li_7 Si_2 S_7 I$ Solid Electrolytes in Solid-State Battery Cathode Composites

Hartel, J. ; Kim, T.FZJ* ; Nascimento Schürhoff, N. ; Kraft, M.FZJ* ; Han, G. ; Chen, R. ; Daniels, L. M. ; Hardwick, L. J. ; Rosseinsky, M. J. (Corresponding author) ; Zeier, W. (Corresponding author)FZJ*

2025
ACS Publications Washington, DC

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Please use a persistent id in citations: doi:10.1021/acsaem.5c03030  doi:10.34734/FZJ-2026-00026

Abstract: The development of solid electrolytes (SEs) for high-performance solid-state batteries (SSBs) requires not only favorable electrochemical stability but also interfacial compatibility with diverse cathode chemistries. In this study, we systematically benchmark recently discovered $Li_7Si_2S_7I$ against the well-established argyrodite $Li_{5.5}PS_{4.5}Cl_{1.5}$ as an SE in composite cathodes. Despite exhibiting comparable oxidative stability, $Li_7Si_2S_7I$ demonstrates markedly different behaviors depending on the cathode chemistry. In composite cathodes with uncoated $LiNi_{0.83}Co_{0.11}Mn_{0.06}O_2$ as the cathode active material and $Li_7Si_2S_7I$ as the electrolyte, rapid degradation occurs, with capacity retention dropping to 5% after 30 cycles, driven by fast degradation kinetics and interfacial instability toward the formation of $SiO_x$ species as a thermodynamic sink. In contrast, sulfur–carbon–$Li_7Si_2S_7I$ composite cathodes show good performance in half-cells, comparable to that of the argyrodite benchmark. The reversible oxidative redox processes of $Li_7Si_2S_7I$ in sulfur-based systems highlight its promise for Li–S and other oxygen-free battery chemistries. Overall, this work emphasizes the importance of a holistic approach to SE evaluation, integrating chemical and electrochemical stability with degradation kinetics, to inform the rational design of next-generation SSB materials.

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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)

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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