Nano/Microstructured Silicon-Graphite Composite Anode for High-Energy-Density Li-Ion Battery

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Growing demand for high-energy-density lithium-ion batteries (LIBs).
• Silicon offers high theoretical capacity but faces challenges like low electrode loading and insufficient areal capacity.
• Graphite is the current industry standard but has limitations in energy density.

Purpose of the Study:

• To enhance graphite electrodes by incorporating modified silicon for improved LIB performance.
• To overcome the limitations of pure silicon and graphite electrodes.
• To develop a scalable method for creating high-performance battery electrode composites.

Main Methods:

• Modification of nano/microstructured silicon with boron doping and carbon nanotube (CNT) wedging (B-Si/CNT).
• Facile and scalable blending process to create a B-Si/CNT-graphite composite (B-Si/CNT@G).
• Electrochemical testing of the composite as an anode in LIBs and in a full battery configuration.

Main Results:

• The modified B-Si/CNT material demonstrated high reversible capacity (~2426 mAh g⁻¹) and improved stability (88.2% retention after 200 cycles).
• The B-Si/CNT@G composite achieved a high areal capacity of 5.2 mAh cm⁻² and excellent cycle retention (83.4% over 100 cycles) at ultrahigh active mass loading (11.2 mg cm⁻²).
• The full battery using B-Si/CNT@G anode and Al2-FCG76 cathode exhibited outstanding energy density (8.0 mWh cm⁻²) and capacity retention (82.5% over 300 cycles).

Conclusions:

• The synergistic effect between modified silicon and graphite significantly enhances electrode performance.
• The developed B-Si/CNT@G composite offers a promising pathway for next-generation high-energy-density LIBs.
• This approach provides a scalable solution for overcoming silicon anode limitations in practical battery applications.