Journal Article

FZJ-2026-04317

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Electrochemical and Spectroscopic Evaluation of $Li_7Si_2S_7I$ Solid Electrolyte in All-Solid-State Batteries

Acín-Lalanza, A. ; Hartel, J. ; Zhang, J. ; Kraft, M.FZJ* ; Chen, R. ; Daniels, L. M. ; Zeier, W. G.FZJ* ; Hardwick, L. J. (Corresponding author) ; Rosseinsky, M. J. (Corresponding author)

2026
ACS Publications Washington, DC

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Please use a persistent id in citations: doi:10.1021/acsaem.6c01833  doi:10.34734/FZJ-2026-04317

Abstract: All-solid-state batteries require solid electrolytes with sufficient oxidative and reductive stability; however, the interfacial behavior of emerging silicon-based sulfide electrolytes remains poorly understood. In particular, the electrochemical stability of $Li_7Si_2S_7I$ under practical cell operation and the separate effects of cathode and anode interfaces on performance degradation have not been clarified. Here, we systematically evaluate $Li_7Si_2S_7I$ in $LiNi_{0.82}Mn_{0.07}Co_{0.11}O_2$ (NMC82) | solid electrolyte | Li-In all-solid-state cells using two- and three-electrode configurations combined with impedance analysis and ex situ Raman and X-ray photoelectron spectroscopy. Three-electrode measurements decouple the interfacial reactions and reveal concurrent interfacial decomposition at both the cathode and anode sides, with dominating effect from the cathode side. Symmetric cell tests using Li-In/$Li_7Si_2S_7I$ composite electrodes confirm slight reductive instability against Li-In for $Li_7Si_2S_7I$ as an anolyte. Spectroscopic analysis identifies polysulfides, oxidized iodide, and oxygenated $SiO_x$ and $SO_x$ species at the $Li_7Si_2S_7I$/NMC82 interface, as well as $In_2S_3$ formation at the $Li_7Si_2S_7I$/Li-In interface. Our findings provide mechanistic insight into the interfacial reactions of Si-based sulfide electrolytes and highlight the importance of electrode-decoupled diagnostics for evaluating the compatibility with electrode materials in all-solid-state batteries.

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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 2026

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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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