Toward Mechanically Stable Silicon-Based Anodes Using Si/SiO _x@C Hierarchical Structures with Well-Controlled...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon-based anodes offer high theoretical capacity for lithium-ion batteries but suffer from poor conductivity and structural degradation.
• These limitations result in significant capacity fading, hindering their commercial viability.
• Developing stable and efficient silicon anodes is crucial for advancing battery technology.

Purpose of the Study:

• To engineer a scalable silicon/silica/carbon (Si/SiOₓ@C) anode architecture.
• To overcome the capacity fading and structural instability issues in silicon anodes.
• To enhance the electrochemical performance and practical applicability of silicon anodes in lithium-ion batteries.

Main Methods:

• Fabrication of the Si/SiOₓ@C anode through simultaneous sintering of SiO/sucrose in an argon atmosphere.
• Post-sintering acid etching to create internal nanovoids within the silica matrix.
• Characterization of the hierarchical structure featuring Si nanocrystals embedded in silica and coated with carbon shells.

Main Results:

• The hierarchical Si/SiOₓ@C anode exhibits uniform Si nanocrystals within silica matrices and carbon shells.
• Achieved a high initial reversible capacity of 1210 mAh g⁻¹.
• Demonstrated stable cycling with 90% capacity retention after 100 cycles and a good rate capability of 850 mAh g⁻¹ at 2.0 A g⁻¹.

Conclusions:

• The designed hierarchical anode architecture improves volumetric efficiency and electrical properties.
• The Si/SiOₓ@C material shows promising electrochemical performance, including high capacity and stability.
• The facile and scalable fabrication method makes this anode material a viable candidate for commercial lithium-ion battery applications.