An innovative strategy for constructing multicore yolk-shell Si/C anodes for lithium-ion batteries

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Silicon anodes offer high capacity for lithium-ion batteries (LIBs) but suffer from volume expansion during cycling.
• Existing yolk-shell structures for silicon anodes often require sacrificial templates and harsh etching, limiting scalability.

Purpose of the Study:

• To develop a scalable and industrially applicable method for fabricating silicon/carbon (Si/C) yolk-shell anodes.
• To investigate the performance enhancement and mechanism of yolk-shell structures in Si anodes.

Main Methods:

• Scalable spray drying technology combined with in-situ growth of metal-organic frameworks (MOFs) at room temperature.
• Controlled adjustment of spray drying parameters and MOF size to tune cavity size and shell integrity.
• Electrochemical characterization and finite element analysis (FEA) to evaluate performance and mechanism.

Main Results:

• Successfully synthesized Si/C composites with a controllable multicore yolk-shell structure without sacrificial templates.
• Achieved high reversible specific capacity (1,054.5 mAh g⁻¹ after 100 cycles at 0.5 A g⁻¹) and excellent long-term stability (734.8 mAh g⁻¹ after 400 cycles at 1 A g⁻¹).
• FEA revealed that the yolk-shell cavities enhance ion diffusion, contributing to improved anode performance.

Conclusions:

• A new, scalable synthetic paradigm for yolk-shell Si-C composites was established using spray drying and MOF templating.
• The yolk-shell architecture effectively mitigates volume expansion and enhances ion diffusion in Si anodes.
• This work provides critical insights into the performance improvement mechanisms of yolk-shell structures for next-generation LIBs.