Chemical Bond Covalency in Superionic Halide Solid-State Electrolytes

Jiamin Fu; Han Su; Jing Luo; Xiaona Li; Jianwen Liang; Changhong Wang; Jung Tae Kim; Yang Hu; Feipeng Zhao; Shumin Zhang; Hui Duan; Xiaoge Hao; Weihan Li; Jian Peng; Jue Liu; Shuo Wang; Tsun Kong Sham; Xueliang Sun

doi:10.1002/anie.202508835

Chemical Bond Covalency in Superionic Halide Solid-State Electrolytes

Jiamin Fu
, Han Su
, Jing Luo
, Xiaona Li
, Jianwen Liang
, Changhong Wang
, Jung Tae Kim
, Yang Hu
, Feipeng Zhao
, Shumin Zhang
, Hui Duan
, Xiaoge Hao
, Weihan Li
, Jian Peng
, Jue Liu
, Shuo Wang
, Tsun Kong Sham
, Xueliang Sun

Powder Diffraction

Research output: Contribution to journal › Article › peer-review

7 Scopus citations

Abstract

Halide solid-state electrolytes (SSEs) are promising superionic conductors with high oxidative stability and ionic conductivity, making them attractive for all-solid-state lithium-ion batteries. However, most studies have focused on ion-stacking structures, overlooking the role of bond characteristics in ionic transport. Here, we investigate bond dynamics and the superionic transition (SIT) in bromide electrolyte, Li₃InBr₆, using synchrotron X-ray techniques and ab initio molecular dynamics (AIMD) simulations. We demonstrate that the SIT in halide SSEs is driven by a thermally induced transition in bonding character (ionic to covalent) rather than a change in crystal phase. AIMD simulations further reveal enhanced Li⁺ diffusion and collective anion motion at elevated temperatures. Expanding our study to Li₃LnBr₆ (Ln = Gd, Tb, Ho, Tm, and Lu), we confirm the widespread occurrence of SIT in this material class, with Li₃GdBr₆ exhibiting the highest ionic conductivity (5.2 mS cm⁻¹ at 298 K). More importantly, the ionic-covalent transition is highly tunable through electrolyte modifications, such as cation/anion substitution and synthesis methods. Our findings provide a new perspective on ionic transport, highlighting the critical role of chemical bond characteristics in halide SSEs.

Original language	English
Article number	e202508835
Journal	Angewandte Chemie - International Edition
Volume	64
Issue number	32
DOIs	https://doi.org/10.1002/anie.202508835
State	Published - Aug 4 2025

Funding

The authors thank the support from the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canada Research Chair Program (CRC), the Canada Foundation for Innovation (CFI), and Western University. The synchrotron-related characterizations were completed at the HXMA, SXRMB, and BXDS beamline at the Canadian Light Source (CLS), which is supported by the Canadian Foundation for Innovation (CFI), the Natural Sciences and Engineering Research Council (NSERC), the National Research Council (NRC), the Canadian Institutes of Health Research (CIHR), the Government of Saskatchewan, and the University of Saskatchewan. The in situ XAS experiments were conducted at the BM-20 beamline at the Advanced Photon Source (APS). J.F. acknowledges the financial support from the program of the China Scholarships Council. J.L. acknowledges the support from the Beijing Natural Science Foundation (JQ22028), National Key R&D Program of China (2022YFB3506300), and National Natural Science Foundation of China (No. 22379127). X.S. and C.W. appreciate the funding support from the National Natural Science Foundation of China (Grant Nos. W2441017, 22409103), the “Innovation Yongjiang 2035” Key R&D Program (Grant Nos. 2024Z040, 2025Z063). Part of this work was conducted at the NOMAD beamlines at ORNL's Spallation Neutron Source, which was sponsored by the Scientific User Facilities Division, Office of Basic Sciences, US Department of Energy. The authors thank the support from the Natural Sciences and Engineering Research Council of Canada (NSERC), the Canada Research Chair Program (CRC), the Canada Foundation for Innovation (CFI), and Western University. The synchrotron‐related characterizations were completed at the HXMA, SXRMB, and BXDS beamline at the Canadian Light Source (CLS), which is supported by the Canadian Foundation for Innovation (CFI), the Natural Sciences and Engineering Research Council (NSERC), the National Research Council (NRC), the Canadian Institutes of Health Research (CIHR), the Government of Saskatchewan, and the University of Saskatchewan. The in situ XAS experiments were conducted at the BM‐20 beamline at the Advanced Photon Source (APS). J.F. acknowledges the financial support from the program of the China Scholarships Council. J.L. acknowledges the support from the Beijing Natural Science Foundation (JQ22028), National Key R&D Program of China (2022YFB3506300), and National Natural Science Foundation of China (No. 22379127). X.S. and C.W. appreciate the funding support from the National Natural Science Foundation of China (Grant Nos. W2441017, 22409103), the “Innovation Yongjiang 2035” Key R&D Program (Grant Nos. 2024Z040, 2025Z063). Part of this work was conducted at the NOMAD beamlines at ORNL's Spallation Neutron Source, which was sponsored by the Scientific User Facilities Division, Office of Basic Sciences, US Department of Energy.

Keywords

Covalency
Halide conductor
Ionic diffusion
Solid-state electrolyte

Access to Document

10.1002/anie.202508835

Cite this

@article{1be2639d677c4619a1b519370eb6cf7f,

title = "Chemical Bond Covalency in Superionic Halide Solid-State Electrolytes",

abstract = "Halide solid-state electrolytes (SSEs) are promising superionic conductors with high oxidative stability and ionic conductivity, making them attractive for all-solid-state lithium-ion batteries. However, most studies have focused on ion-stacking structures, overlooking the role of bond characteristics in ionic transport. Here, we investigate bond dynamics and the superionic transition (SIT) in bromide electrolyte, Li3InBr6, using synchrotron X-ray techniques and ab initio molecular dynamics (AIMD) simulations. We demonstrate that the SIT in halide SSEs is driven by a thermally induced transition in bonding character (ionic to covalent) rather than a change in crystal phase. AIMD simulations further reveal enhanced Li⁺ diffusion and collective anion motion at elevated temperatures. Expanding our study to Li3LnBr6 (Ln = Gd, Tb, Ho, Tm, and Lu), we confirm the widespread occurrence of SIT in this material class, with Li3GdBr6 exhibiting the highest ionic conductivity (5.2 mS cm−1 at 298 K). More importantly, the ionic-covalent transition is highly tunable through electrolyte modifications, such as cation/anion substitution and synthesis methods. Our findings provide a new perspective on ionic transport, highlighting the critical role of chemical bond characteristics in halide SSEs.",

keywords = "Covalency, Halide conductor, Ionic diffusion, Solid-state electrolyte",

author = "Jiamin Fu and Han Su and Jing Luo and Xiaona Li and Jianwen Liang and Changhong Wang and Kim, \{Jung Tae\} and Yang Hu and Feipeng Zhao and Shumin Zhang and Hui Duan and Xiaoge Hao and Weihan Li and Jian Peng and Jue Liu and Shuo Wang and Sham, \{Tsun Kong\} and Xueliang Sun",

note = "Publisher Copyright: {\textcopyright} 2025 The Author(s). Angewandte Chemie International Edition published by Wiley-VCH GmbH.",

year = "2025",

month = aug,

day = "4",

doi = "10.1002/anie.202508835",

language = "English",

volume = "64",

journal = "Angewandte Chemie - International Edition",

issn = "1433-7851",

publisher = "wiley",

number = "32",

}

TY - JOUR

T1 - Chemical Bond Covalency in Superionic Halide Solid-State Electrolytes

AU - Fu, Jiamin

AU - Su, Han

AU - Luo, Jing

AU - Li, Xiaona

AU - Liang, Jianwen

AU - Wang, Changhong

AU - Kim, Jung Tae

AU - Hu, Yang

AU - Zhao, Feipeng

AU - Zhang, Shumin

AU - Duan, Hui

AU - Hao, Xiaoge

AU - Li, Weihan

AU - Peng, Jian

AU - Liu, Jue

AU - Wang, Shuo

AU - Sham, Tsun Kong

AU - Sun, Xueliang

PY - 2025/8/4

Y1 - 2025/8/4

N2 - Halide solid-state electrolytes (SSEs) are promising superionic conductors with high oxidative stability and ionic conductivity, making them attractive for all-solid-state lithium-ion batteries. However, most studies have focused on ion-stacking structures, overlooking the role of bond characteristics in ionic transport. Here, we investigate bond dynamics and the superionic transition (SIT) in bromide electrolyte, Li3InBr6, using synchrotron X-ray techniques and ab initio molecular dynamics (AIMD) simulations. We demonstrate that the SIT in halide SSEs is driven by a thermally induced transition in bonding character (ionic to covalent) rather than a change in crystal phase. AIMD simulations further reveal enhanced Li⁺ diffusion and collective anion motion at elevated temperatures. Expanding our study to Li3LnBr6 (Ln = Gd, Tb, Ho, Tm, and Lu), we confirm the widespread occurrence of SIT in this material class, with Li3GdBr6 exhibiting the highest ionic conductivity (5.2 mS cm−1 at 298 K). More importantly, the ionic-covalent transition is highly tunable through electrolyte modifications, such as cation/anion substitution and synthesis methods. Our findings provide a new perspective on ionic transport, highlighting the critical role of chemical bond characteristics in halide SSEs.

AB - Halide solid-state electrolytes (SSEs) are promising superionic conductors with high oxidative stability and ionic conductivity, making them attractive for all-solid-state lithium-ion batteries. However, most studies have focused on ion-stacking structures, overlooking the role of bond characteristics in ionic transport. Here, we investigate bond dynamics and the superionic transition (SIT) in bromide electrolyte, Li3InBr6, using synchrotron X-ray techniques and ab initio molecular dynamics (AIMD) simulations. We demonstrate that the SIT in halide SSEs is driven by a thermally induced transition in bonding character (ionic to covalent) rather than a change in crystal phase. AIMD simulations further reveal enhanced Li⁺ diffusion and collective anion motion at elevated temperatures. Expanding our study to Li3LnBr6 (Ln = Gd, Tb, Ho, Tm, and Lu), we confirm the widespread occurrence of SIT in this material class, with Li3GdBr6 exhibiting the highest ionic conductivity (5.2 mS cm−1 at 298 K). More importantly, the ionic-covalent transition is highly tunable through electrolyte modifications, such as cation/anion substitution and synthesis methods. Our findings provide a new perspective on ionic transport, highlighting the critical role of chemical bond characteristics in halide SSEs.

KW - Covalency

KW - Halide conductor

KW - Ionic diffusion

KW - Solid-state electrolyte

UR - https://www.scopus.com/pages/publications/105008409593

U2 - 10.1002/anie.202508835

DO - 10.1002/anie.202508835

M3 - Article

C2 - 40437811

AN - SCOPUS:105008409593

SN - 1433-7851

VL - 64

JO - Angewandte Chemie - International Edition

JF - Angewandte Chemie - International Edition

IS - 32

M1 - e202508835

ER -

Chemical Bond Covalency in Superionic Halide Solid-State Electrolytes

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Cite this