Promoting Li Transfer and Storage in Si Anode Through Dynamically Precise Modulation of Constructed Carbon Coating

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Silicon anodes offer high capacity for lithium-ion batteries but suffer from volume expansion and poor ion diffusion.
• Carbon coatings are crucial for improving the cycling stability of silicon anodes.

Purpose of the Study:

• To design and evaluate three distinct carbon coating microstructures for silicon anodes.
• To establish the relationship between carbon coating microstructure and electrochemical performance.
• To provide insights into rational design of advanced anode materials.

Main Methods:

• Fabrication and characterization of three types of carbon coatings on silicon anodes.
• Electrochemical performance testing (cycling stability, rate capability).
• In situ electron microscopy with deep learning (DL) for observing silicon swelling.
• Li+ diffusion kinetics and interfacial composition analysis.

Main Results:

• A hard-carbon-like coating with expanded graphite and pores (EG/P) demonstrated superior Li+/electron diffusion channels.
• The EG/P coating effectively buffered silicon volume expansion during lithiation.
• Electrode performance showed enhanced electrochemical stability and rate capability compared to conventional coatings.
• The strategy's applicability was validated for other alloy-type anodes (Ge, Sn).

Conclusions:

• The rational design of carbon coating microstructure is key to overcoming silicon anode limitations.
• The EG/P coating offers a promising strategy for high-performance lithium-ion battery anodes.
• This approach can be extended to other high-capacity alloy anode materials.