Unprecedented Self-Healing Effect of Li₆ PS₅ Cl-Based All-Solid-State Lithium Battery

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Argyrodite Li₆ PS₅ Cl is a high Li⁺ conductivity material for solid-state electrolytes (SSEs).
• Its narrow electrochemical window and interface instability limit applications in high-energy all-solid-state lithium batteries (ASSLBs).

Purpose of the Study:

• Investigate the electrochemical stability and self-healing behavior of Li₆ PS₅ Cl.
• Understand the mechanism behind failure and healing in Li₆ PS₅ Cl based cells.

Main Methods:

• Fabrication and cycling of Li₆ PS₅ Cl-C/Li₆ PS₅ Cl/Li and Li/Li₆ PS₅ Cl/Li cells.
• In-depth analysis using X-ray photoelectron spectroscopy, in situ Raman spectroscopy, and in situ electrochemical impedance spectroscopy.

Main Results:

• Observed recurring electrochemical failure and healing phenomena in Li₆ PS₅ Cl cells.
• Demonstrated that self-healing is controllable by the charge-discharge voltage range.
• Revealed reversible Li₆ PS₅ Cl decomposition and metallic lithium growth within the electrolyte.

Conclusions:

• The self-healing behavior in Li₆ PS₅ Cl is attributed to reciprocating lithium growth and reversible decomposition reactions.
• This mechanism is crucial for advancing sulfide-based SSEs and guiding interface modification for ASSLBs.