Si@C Microsphere Composite with Multiple Buffer Structures for High-Performance Lithium-Ion Battery Anodes.

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Silicon (Si) anodes are promising for high-capacity lithium-ion batteries but suffer from pulverization and poor conductivity.
• Existing strategies often fail to fully address the volume expansion issue during cycling.

Purpose of the Study:

• To engineer a Si@C microsphere composite with enhanced structural integrity and electrochemical performance.
• To mitigate the critical drawbacks of silicon anodes for next-generation energy storage.

Main Methods:

• Hydrothermal treatment was employed to synthesize the Si@C composite.
• Ferric citrate was used as a carbon source to create a homogeneous mesoporous carbon layer encapsulating Si nanoparticles with a SiO_x buffer layer.
• Carbon nanotubes were incorporated to form a robust framework.

Main Results:

• The Si@C composite features multiple buffer structures (SiO_x layer, mesoporous carbon, carbon nanotube network) that effectively suppress volume expansion and enhance electrolyte infiltration.
• The composite exhibits a high initial charge/discharge capacity of 2956/4197 mAh g^-1 at 0.42 A g^-1.
• The electrodes demonstrate excellent rate capability and stable cycling performance for up to 800 cycles.

Conclusions:

• The developed Si@C microsphere composite effectively addresses the limitations of silicon anodes.
• The synergistic effect of multiple buffer structures significantly improves the electrochemical performance and durability of Si anodes.
• This work offers a promising strategy for developing high-performance silicon-based anodes for lithium-ion batteries.