Fluorinated organosilane polycondensation enables a robust Si anode for lithium storage

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Silicon (Si) anodes offer high theoretical capacity for lithium-ion batteries but suffer from poor cycling stability due to large volume expansion.
• Developing stable anode materials is crucial for next-generation energy storage solutions.

Purpose of the Study:

• To develop a robust silicon anode with enhanced cycling stability and long cycle life.
• To investigate the effect of fluorine doping on the structure and electrochemical performance of Si/SiO2/C composite coatings.

Main Methods:

• Utilized fluorinated organosilane polycondensation chemistry to create F-doped SiO2/C composite coatings on Si anodes.
• Characterized the coating composition and structure using advanced analytical techniques.
• Evaluated the electrochemical performance of the modified Si anodes in lithium-ion cells.

Main Results:

• Achieved a robust Si anode with an F-doped SiO2/C composite coating.
• F-doping promoted the formation of a coating rich in less electrochemically active Si4+ species.
• An LiF-rich solid-state electrolyte interphase was formed, enhancing anode stability.
• The Si anode demonstrated a long cycle life of 500 cycles at high current densities.

Conclusions:

• Fluorine doping is an effective strategy to improve the stability and performance of Si anodes.
• The developed F-doped Si anode exhibits excellent potential for high-performance lithium storage applications.
• The formation of an LiF-rich interphase is key to achieving long cycle life.