Artificial Solid Electrolyte Interphase-Protected LixSi Nanoparticles: An Efficient and Stable Prelithiation Reagent...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Prelithiation is crucial for compensating lithium loss in lithium-ion batteries, especially during solid electrolyte interphase (SEI) formation.
• Lithium-silicon (LixSi) nanoparticles are effective prelithiation reagents but require improved chemical stability for battery processing.

Purpose of the Study:

• To develop a surface modification method to enhance the stability of LixSi nanoparticles.
• To create a protective coating on LixSi nanoparticles for improved ambient stability.

Main Methods:

• Synthesized LixSi nanoparticles via thermal alloying.
• Applied a surface modification using 1-fluorodecane reduction to form a protective coating.
• Characterized the coating composition (LiF, lithium alkyl carbonate with hydrophobic chains) and stability.

Main Results:

• The surface coating effectively passivates LixSi nanoparticles against ambient conditions.
• Protected LixSi NPs demonstrated a high prelithiation capacity of 2100 mA h g⁻¹, with minimal decay in dry air over 5 days.
• Maintained significant capacity (1600 mA h g⁻¹) even in humid air (∼10% RH).
• Successfully prelithiated silicon, tin, and graphite anodes, eliminating irreversible first-cycle capacity loss.

Conclusions:

• Surface-modified LixSi nanoparticles provide a stable and high-capacity prelithiation solution.
• This approach effectively mitigates irreversible capacity loss in lithium-ion batteries.
• Enables the development of next-generation high-energy-density lithium-ion batteries.