Li₃TiCl₆ as ionic conductive and compressible positive electrode active material for all-solid-state lithium-based...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• All-solid-state Li-based batteries require active materials with ionic conductivity and compressibility for enhanced performance.
• These properties can reduce the need for solid-state electrolytes, allowing for higher active material loading.
• Current materials often lack the necessary combination of ionic conductivity and mechanical compressibility.

Purpose of the Study:

• To synthesize and evaluate lithium titanium chloride (Li₃TiCl₆) as a novel active material for all-solid-state Li-based batteries.
• To investigate the ionic conductivity and compressibility of Li₃TiCl₆ at room temperature.
• To assess the electrochemical performance and cycling stability of composite electrodes containing Li₃TiCl₆.

Main Methods:

• Synthesis of Li₃TiCl₆.
• Measurement of ionic conductivity at room temperature (25°C).
• Fabrication and electrochemical testing of composite electrodes (95 wt.% Li₃TiCl₆) with Li-In alloy anodes and Li₆PS₅Cl/Li₂ZrCl₆ solid electrolytes under applied pressure (1.5 tons).
• Assembly and testing of a "single Li₃TiCl₆" cell.

Main Results:

• Li₃TiCl₆ exhibits room-temperature ionic conductivity of 1.04 mS cm^-1 at 25°C.
• Composite electrodes achieved an initial discharge capacity of ~90 mAh g^-1 and an average voltage of ~2.53 V.
• Over 62% capacity retention was observed after 2500 cycles at 92.5 mA g^-1 under 1.5 tons of pressure.
• A "single Li₃TiCl₆" cell demonstrated its potential as a multifunctional component.

Conclusions:

• Li₃TiCl₆ is a promising candidate for room-temperature ionic conductive and compressible active materials in all-solid-state batteries.
• The material facilitates high mass loading and long-term cycling stability.
• Li₃TiCl₆ offers a unique potential for simplified battery architectures, acting as a single-component electrode.