Carbon Microstructure Dependent Li-Ion Storage Behaviors in SiO_x /C Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon oxide (SiOₓ) anodes offer improved cycle life compared to silicon, positioning them as alternatives to graphite in lithium-ion batteries.
• SiOₓ is often composited with carbon to enhance its electrochemical performance and cycle life.
• The influence of carbon microstructure on lithium-ion storage within SiOₓ/carbon composites remains underexplored.

Purpose of the Study:

• To investigate how carbon microstructure affects lithium-ion diffusion pathways (intergranular vs. intragranular) in SiOₓ/carbon anodes.
• To elucidate the relationship between carbon disorder, diffusion characteristics, and the compatibility with SiOₓ.
• To establish a rational strategy for optimizing SiOₓ/carbon anode performance.

Main Methods:

• Quantitative calculations to model lithium-ion diffusion.
• In situ X-ray diffraction (XRD) characterization to observe structural changes.
• Electrochemical performance testing of SiOₓ/carbon anodes with varying carbon microstructures.

Main Results:

• Carbon disorder dictates the ratio of intergranular to intragranular lithium-ion diffusion.
• Optimized intergranular diffusion, induced by rational carbon disorder, benefits the phase transition of SiOₓ/carbon.
• Specific carbon microstructures lead to improved electrochemical performance and compatibility with SiOₓ.

Conclusions:

• The microstructure of carbon is a critical factor in determining the electrochemical performance of SiOₓ/carbon anodes.
• Controlling carbon disorder can optimize lithium-ion diffusion and phase transitions, enhancing battery performance.
• This study provides a rational strategy for the future development of high-performance SiOₓ/carbon anodes.