Conductive rigid skeleton supported silicon as high-performance Li-ion battery anodes

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Silicon (Si) anodes offer high theoretical capacity for lithium-ion batteries but suffer from significant volume expansion during cycling.
• Developing strategies to mitigate Si volume expansion and enhance conductivity is crucial for practical applications.

Purpose of the Study:

• To develop a cost-effective and scalable method for preparing a core-shell structured Si/B(4)C composite with graphite coating.
• To enhance the electrochemical performance, particularly rate capability and long-term stability, of Si-based anodes.

Main Methods:

• Ball-milling process utilizing boron carbide (B(4)C) as micro/nano-millers to break down micron-sized Si.
• In-situ formation of sub-10 nm Si particles supported by a conductive B(4)C rigid skeleton.
• Coating the Si/B(4)C composite with graphitic layers to improve conductivity and stability.

Main Results:

• The developed Si/B(4)C/graphite (SBG) composite anode exhibits high efficiency and exceptional rate performance.
• The material demonstrates excellent cyclability with a specific capacity of ~822 mAh·g⁻¹ and ~94% capacity retention over 100 cycles at 0.3 C.
• The B(4)C component acts as a conductive skeleton and milling agent, effectively alleviating Si volume expansion.

Conclusions:

• The core-shell structured SBG composite offers a promising solution for high-performance and stable Si-based anodes.
• The cost-effective and scalable manufacturing method using commercially available materials is suitable for large-scale production.
• This material has significant potential for practical energy storage applications requiring high capacity and long-term stability.