Electrochemically Stable Li3- xIn1- xHfxCl6 Halide Solid Electrolytes for All-Solid-State Batteries

Heng Wang; Yuxiang Li; Ya Tang; Daixin Ye; Ting He; Hongbin Zhao; Jiujun Zhang

doi:10.1021/acsami.2c21022

Electrochemically Stable Li_{3- x}In_{1- x}Hf_xCl₆ Halide Solid Electrolytes for All-Solid-State Batteries

ACS Appl Mater Interfaces. 2023 Feb 1;15(4):5504-5511. doi: 10.1021/acsami.2c21022. Epub 2023 Jan 20.

Authors

Heng Wang¹, Yuxiang Li¹, Ya Tang¹, Daixin Ye^{1

2}, Ting He¹, Hongbin Zhao¹, Jiujun Zhang^{1

2}

Affiliations

¹ Department of Chemistry, School of Science, Shanghai University, No. 99, Shangda Road, Shanghai 200444, China.
² Institute for Sustainable Energy, School of Science, Shanghai University, No. 99, Shangda Road, Shanghai 200444, China.

PMID: 36662742
DOI: 10.1021/acsami.2c21022

Abstract

Halide solid electrolytes (SEs) stand out among the many different types of SEs owing to their high ionic conductivity and excellent oxidative stability. Aliovalent substitution is a common strategy to enhance the ionic conductivity of halide electrolytes, but this strategy significantly decreases their electrochemical stability. Herein, we report Hf-substituted Li₃InCl₆ (Li_3-xIn_1-xHf_xCl₆, 0 ≤ x ≤ 0.7) SEs, in which a low concentration (0.1 ≤ x ≤ 0.5) of Hf enhances the ionic conductivity without affecting the electrochemical stability. Among them, Li_2.7In_0.7Hf_0.3Cl₆ exhibits a high ionic conductivity of 1.28 mS cm^-1 and a wide electrochemical stability window of 2.68-4.22 V. All-solid-state batteries fabricated using Li_2.7In_0.7Hf_0.3Cl₆ SE present high discharge capacity and good cycling stability at 25 °C. Furthermore, we summarize the methods of crystal structure regulation by which aliovalent substitution of halide SEs is achieved and discuss potential research directions in the design of novel halide SEs with high ionic conductivity and electrochemical stability.

Keywords: aliovalent substitution; electrochemical stability; halide solid electrolyte; ionic conductivity.