Functional Interface Modifier with Visualizations of Dendrite Growth and Heat Evolution in Lithium Metal Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium-metal anodes are crucial for high-energy-density batteries.
• Lithium dendrite formation presents a significant safety challenge, hindering practical application.

Purpose of the Study:

• To develop a multipurpose artificial passivation layer for lithium-metal anodes.
• To suppress dendrite growth and electrolyte decomposition for enhanced safety and stability.

Main Methods:

• A facile and versatile approach using stannic chloride as a sacrificial agent to create a bilayered structure (LiCl-rich and Li-Sn alloy) on the lithium-metal interface.
• Operando confocal optical microscopy (OM) for visualizing lithium growth phenomena.
• Heat evolution measurements and in situ electrochemical impedance spectroscopy (EIS) for analyzing interfacial reactions.

Main Results:

• The artificial passivation layer successfully reinforced uniform lithium flux and suppressed electrolyte decomposition.
• Demonstrated dendrite-free lithium deposition and uniform lithium growth, enabling operation at high current densities (5 mA cm⁻²/5 mAh cm⁻²) for over 600 hours.
• Achieved excellent capacity retention (e.g., 97.1% after 360 cycles at 0.5 mA cm⁻²) with a LiFePO₄ cathode.

Conclusions:

• The developed passivation strategy effectively stabilizes the lithium-metal anode interface.
• This solvent- and binder-free method enables guided lithium growth, paving the way for safe and high-performance lithium-metal batteries.