Cation-Anion-Engineering Modified Oxychloride Zr-Based Lithium Superionic Conductors for All-Solid-State Lithium...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Lithium-ion batteries require efficient solid electrolytes (SEs) for safety and performance.
• Halide SEs like Li₂ZrCl₆ offer stability but suffer from low room-temperature ionic conductivity.
• Existing methods focus on single sublattice modifications, presenting limitations.

Purpose of the Study:

• To introduce a novel cation and anion-sublattice-engineering (CASE) strategy to enhance ionic conductivity in Li₂ZrCl₆.
• To increase the amorphous content of the solid electrolyte through simultaneous cation and anion modification.
• To develop a high-performance solid electrolyte for all-solid-state lithium batteries.

Main Methods:

• Incorporation of Cu²⁺ and O²⁻ into the Li₂ZrCl₆ structure.
• Structural characterization using X-ray absorption spectroscopy and neutron diffraction.
• Performance evaluation via ab initio molecular dynamics and all-solid-state battery cycling.

Main Results:

• The amorphous Li₂.₁Zr₀.₉₅Cu₀.₀₅Cl₄.₄O₀.₈ achieved an ionic conductivity of 2.05 mS cm⁻¹ at 25 °C.
• All-solid-state batteries demonstrated excellent long-term cycling stability, retaining 90.3% capacity after 1000 cycles.
• The CASE strategy significantly improved ionic conductivity compared to unmodified Li₂ZrCl₆.

Conclusions:

• The CASE strategy effectively enhances ionic conductivity by increasing amorphous content in halide solid electrolytes.
• The developed amorphous electrolyte shows promise for high-performance and stable all-solid-state lithium batteries.
• This approach opens new avenues for designing advanced solid electrolytes with high ionic conductivity.