Solubility-Difference-Driven Strategy for Constructing Core-Shell Structure Si@C Anodes: Ammonia-Assisted Carbon...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Silicon anodes offer high theoretical capacity but suffer from poor conductivity and volume expansion during cycling.
• Carbon materials are often used to composite with silicon to improve anode performance.
• Existing methods for Si@C anode fabrication can be complex and difficult to scale.

Purpose of the Study:

• To develop a novel, scalable method for creating core-shell structured silicon-carbon (Si@C) anodes.
• To enhance the electrochemical performance and cycling stability of silicon anodes for lithium-ion batteries.
• To investigate the role of copper nanoparticles in improving the anode's conductivity and structural integrity.

Main Methods:

• A solubility-difference-driven approach was employed using poly(vinyl alcohol) and basic copper carbonate.
• A uniform carbon shell embedded with copper nanoparticles was formed on silicon nanoparticles (Si@C-3).
• Electrochemical performance was evaluated through galvanostatic cycling at various current densities.

Main Results:

• The optimized Si@C-3 anode demonstrated a high reversible capacity of 1346.1 mAh g^-1 at 0.2 A g^-1 after 150 cycles.
• Excellent cycling stability was observed, retaining 559.1 mAh g^-1 at 2 A g^-1 after 300 cycles and 465.8 mAh g^-1 at 6 A g^-1.
• The core-shell structure with copper nanoparticles effectively mitigated volume expansion and improved conductivity.

Conclusions:

• The solubility-difference strategy offers a feasible and scalable pathway for producing high-performance Si/C composite anodes.
• The developed Si@C-3 anode shows significant promise for commercial lithium-ion battery applications.
• The embedded copper nanoparticles play a crucial role in enhancing electrode kinetics and structural stability.