Controllable SiO Coating Layer Promotes High Stable Si Anode for Lithium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon (Si) is a promising anode material for next-generation lithium-ion batteries due to its high theoretical energy density.
• Si anodes suffer from severe volume expansion and continuous interfacial side reactions, limiting their practical application.
• A robust coating layer can effectively suppress these detrimental effects.

Purpose of the Study:

• To synthesize and investigate Si@SiO2 materials for enhanced lithium-ion battery anode performance.
• To explore the etching/oxidation mechanism of Si in alkaline conditions.
• To evaluate the electrochemical properties of the modified Si anodes.

Main Methods:

• Synthesis of Si@SiO2 via a solid-liquid reaction using LiOH solution etching.
• Investigation of the etching/oxidation mechanism of Si under alkaline conditions.
• Electrochemical performance testing of Si@SiO2 as anode materials in lithium-ion batteries.

Main Results:

• Si@SiO2 material with high specific surface area, porosity, and controllable coating was successfully synthesized.
• The etching-oxidation process created a stable solid electrolyte interphase (SEI) with high Li+ conductivity.
• The porous structure reduced Si volume expansion by approximately 110%.
• The modified anode achieved a high specific capacity of 3101.5 mAh g-1, retaining 841.0 mAh g-1 after 500 cycles at 1 A g-1.

Conclusions:

• The Si@SiO2 composite material effectively addresses the challenges of Si anodes in lithium-ion batteries.
• The synergistic etching-oxidation strategy significantly enhances electrochemical performance and cycle stability.
• This approach offers a viable pathway for developing high-energy-density silicon-based anodes.