Novel binary regulated silicon-carbon materials as high-performance anodes for lithium-ion batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon anodes offer high theoretical capacity but suffer from volume expansion, unstable solid electrolyte interphase (SEI), and poor conductivity, hindering practical battery applications.
• Existing solutions often involve complex synthesis or fail to fully address silicon's inherent drawbacks.

Purpose of the Study:

• To develop novel binary regulated silicon-carbon materials (Si/BPC) to address the limitations of silicon anodes.
• To systematically investigate the effects of binary doping (Boron and Phosphorus) on the morphology, structure, and electrochemical performance of silicon-carbon composites.

Main Methods:

• Sol-gel procedure combined with single carbonization for Si/BPC synthesis.
• Systematic analytical techniques to examine material properties and electrochemical performance.
• Electrochemical testing including cycling stability, rate capability, and impedance spectroscopy.

Main Results:

• The optimized Si/BPC composite demonstrated a high discharge specific capacity of 1021.6 mAh g^-1 after 180 cycles at 1000 mA g^-1 with 99.27% coulombic efficiency.
• Excellent rate performance was observed, with a capacity of 1003.2 mAh g^-1 at 5000 mA g^-1 and recovery to 2838.6 mAh g^-1 at 200 mA g^-1.
• Co-doping with Boron and Phosphorus elements synergistically improved lithium-ion diffusion kinetics, reduced electrochemical impedance to 45.75 Ω, and created more active sites for Li⁺ storage.

Conclusions:

• Binary regulated silicon-carbon materials (Si/BPC) effectively mitigate the challenges associated with silicon anodes.
• The synergistic effect of B and P co-doping significantly enhances electrochemical properties, including ion diffusion and charge transfer.
• This research presents a promising strategy for developing high-performance silicon-based anodes for advanced lithium-ion batteries.