Interfacial Electronic Coupling in Si@SiC@EG Core-Shell Architectures Enables High-Capacity and Long-Life Lithium-Ion...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Silicon anodes offer high theoretical capacity for next-generation lithium-ion batteries.
• Volume expansion during cycling causes capacity fading in silicon anodes.
• Developing stable silicon-based anodes is crucial for high-energy storage.

Purpose of the Study:

• To engineer a stable silicon anode with enhanced electrochemical performance.
• To address the volume fluctuation issue in silicon anodes using a core-shell structure.
• To investigate the structural and electrochemical properties of a Si@SiC@EG nanocomposite.

Main Methods:

• In situ epitaxial growth of Si@SiC@epitaxial Graphene (EG) core-shell nanocomposite.
• Electrochemical characterization including cycling performance and rate capability tests.
• Structural analysis using ex situ X-ray diffraction, in situ Raman spectroscopy, and ex situ X-ray photoelectron spectroscopy.
• Density functional theory (DFT) calculations for interfacial properties.

Main Results:

• The Si@SiC@EG anode demonstrated a high reversible capacity of 1747 mAh g⁻¹ at 0.1 A g⁻¹.
• Exceptional durability was observed, retaining 872 mAh g⁻¹ after 2000 cycles at 1 A g⁻¹.
• DFT calculations confirmed improved Li⁺ ion transport kinetics due to strong interfacial coupling.

Conclusions:

• The Si@SiC@EG heterostructure effectively buffers silicon volume expansion, enhancing anode stability.
• The nanocomposite exhibits excellent electrochemical performance, making it a promising candidate for high-energy lithium-ion batteries.
• This engineered material provides a viable platform for developing advanced energy storage solutions.