Ultrathin Carbon Sheet Obtained by Self-Template Method toward Highly Effective Charge Transfer for Si-Based Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Silicon anodes offer high lithium storage capacity but suffer from large volume changes during cycling.
• Stable charge transfer and mechanical buffering are crucial for silicon anode performance.

Purpose of the Study:

• To develop a novel carbon-based conductive network for silicon anodes.
• To enhance the electrochemical performance and cycling stability of silicon anodes.

Main Methods:

• Fabrication of a composite using freeze-drying and copyrolysis of citric acid and hydroxylated Si NPs.
• Creation of an ultrathin, N-doped carbon sheet skeleton around silicon nanoparticles (Si-OH@NC).
• Electrochemical testing to evaluate cycle performance and rate capability.

Main Results:

• The N-doped carbon sheet network effectively buffers mechanical stress and prevents particle slip.
• Enhanced point-to-surface contact and continuous electrical pathways promote rapid electron transfer.
• The electrode achieved a reversible capacity of 1001.9 mAh g⁻¹ at 1 A g⁻¹ after 500 cycles.
• Excellent rate performance was observed with 86.8% retention at 1 A g⁻¹ and 65.8% at 3 A g⁻¹.

Conclusions:

• The proposed N-doped carbon sheet network significantly improves the lithium storage performance of silicon anodes.
• This strategy provides a new approach for designing high-performance electrodes for energy storage devices.
• The concept is applicable to other active materials with substantial volume changes.