Dual Bond Enhanced Multidimensional Constructed Composite Silicon Anode for High-Performance Lithium Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Silicon-based anode materials are crucial for increasing lithium-ion battery energy density.
• Current silicon anodes require enhanced cycle stability and reversible capacity.
• MXene, silicon, and carbon nanotube (CNT) composites offer potential for advanced battery anodes.

Purpose of the Study:

• To develop novel dual bond restricted MXene-Si-CNT composite anode materials.
• To improve the electrochemical performance, specifically cycle stability and reversible capacity, of silicon-based anodes.
• To investigate the role of dual bonds in enhancing material stability.

Main Methods:

• Synthesis of MXene-Si-CNT composites using a facile ball-milling method.
• Characterization of dual bonds using X-ray photoelectron spectroscopy (XPS).
• Theoretical calculations to determine spontaneous reaction energy for Ti-Si and C-Si bonds.

Main Results:

• Dual bonds (Ti-Si and C-Si) were confirmed by XPS and theoretical calculations (reaction energies -0.190 and -0.429 eV/atom).
• The MXene-Si-CNT composite (60 wt% silicon) exhibited enhanced electrochemical performance.
• Achieved ~80% capacity retention after 200 cycles and a reversible capacity of 841 mAh g⁻¹ at 2 A g⁻¹.

Conclusions:

• Dual bond restriction and multidimensional architecture significantly improve the cycle stability of silicon-based anodes.
• The developed MXene-Si-CNT composite represents a promising strategy for high-performance anode materials.
• This method can potentially be extended to other anode materials facing volumetric change issues.