Prelithiated Surface Oxide Layer Enabled High-Performance Si Anode for Lithium Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon anodes are promising for high-capacity lithium-ion batteries.
• Silicon anodes suffer from low initial Coulombic efficiency and poor cycling stability.
• Silicon oxide (SiO_x) coatings improve stability but can impede ion diffusion.

Purpose of the Study:

• To address the limitations of SiO_x-coated silicon anodes.
• To enhance initial Coulombic efficiency and lithium-ion diffusion.
• To develop a stable and high-performance silicon anode for lithium-ion batteries.

Main Methods:

• Preparation of selectively prelithiated Si@SiO_x (Si@Li₂SiO₃) anode using a facile strategy.
• Electrochemical testing of Si@Li₂SiO₃ as an anode material.
• Assembly and testing of a full cell using LiFePO₄ cathode and Si@Li₂SiO₃ anode.

Main Results:

• Si@Li₂SiO₃ anode achieved an initial Coulombic efficiency (ICE) of 89.1%.
• Demonstrated excellent rate performance (959 mA h g^-1 at 30 A g^-1) and capacity retention (3215 mA h g^-1).
• Full cell exhibited a high ICE of 91.1% and superior long-term cycling stability.

Conclusions:

• The Si@Li₂SiO₃ anode effectively resolves issues of low ICE and sluggish ion diffusion.
• The prelithiated coating enhances electrode integrity and reduces irreversible reactions.
• This strategy offers a promising pathway for advanced silicon anodes in lithium-ion batteries.