A Li-Rich Fluorinated Lithium Zirconium Chloride Solid Electrolyte for 4.8 V-Class All-Solid-State Batteries

Yini Zhang; Zhenyou Song; Likuo Wang; Yuwei Chen; Qian Yu; Guang Sun; Ya Deng; Wang Hay Kan; Wei Luo

doi:10.1002/smll.202407418

A Li-Rich Fluorinated Lithium Zirconium Chloride Solid Electrolyte for 4.8 V-Class All-Solid-State Batteries

Small. 2024 Nov 5:e2407418. doi: 10.1002/smll.202407418. Online ahead of print.

Authors

Yini Zhang¹, Zhenyou Song¹, Likuo Wang¹, Yuwei Chen¹, Qian Yu¹, Guang Sun¹, Ya Deng¹, Wang Hay Kan^{2

3}, Wei Luo¹

Affiliations

¹ Institute of New Energy for Vehicles, School of Materials Science and Engineering, Tongji University, Shanghai, 201804, China.
² Spallation Neutron Source Science Center, Dongguan, 523803, China.
³ Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China.

PMID: 39498695
DOI: 10.1002/smll.202407418

Abstract

Chloride solid-state electrolytes (SEs) represent an important advance for applications in all-solid-state batteries (ASSBs). Among various chloride SEs, lithium zirconium chloride (Li₂ZrCl₆) is an attractive candidate considering the high natural abundance of Zr. However, Li₂ZrCl₆ meets the challenge in practical ASSBs because of its limited ionic conductivity and instability when paired with high-voltage cathodes. This is a major drawback, which can result in a high internal resistance, a low capacity utilization of cathode, and poor cycle stability, especially at high voltage. Existing methods cannot achieve simultaneous enhancement on both ionic conductivity and high-voltage stability due to a trade-off between lithium-ion migration and structural stability. Here a two-pronged strategy based on partial fluorination and incorporation of lithium ions in excess of stoichiometric ratios is introduced that enables high-voltage stability while increasing ionic conductivity concurrently. The Li-rich fluorinated halide SE (Li_2.3ZrCl_6.1F_0.2) exhibits a significant advancement in performance, with an ionic conductivity that is double that of the pristine Li₂ZrCl₆ and much better high-voltage stability. By leveraging Li_2.3ZrCl_6.1F_0.2 with the LiCoO₂ cathode and the Li-In anode, the all-solid-state cell exhibits a remarkable initial specific capacity (198.0 mAh g^-1 at 0.1 C) and a high capacity retention (78.5% after 150 cycles) within 3.0-4.8 V.

Keywords: Li‐richening; fluorination; high‐voltage stability; solid electrolyte; solid‐state cell.

Abstract

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