Micrometer-Sized SiMg_y O_x with Stable Internal Structure Evolution for High-Performance Li-Ion Battery Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Micrometer-sized silicon (Si)-based anodes are crucial for high-energy, low-cost energy storage.
• Volume expansion during cycling causes structural damage and performance degradation in SiO$_{x}$ microparticles.
• Developing stable Si-based anodes is essential for advanced lithium-ion batteries.

Purpose of the Study:

• To develop structurally stable micrometer-sized silicon oxide (SiO$_{x}$) anode materials.
• To enhance the electrochemical performance and cycle life of Si-based anodes.
• To mitigate the volume variation issue in SiO$_{x}$ microparticles during lithium (Li) uptake/release.

Main Methods:

• In situ preparation of magnesium-doped SiO$_{x}$ (SiMg$_{y}$O$_{x}$) microparticles.
• Characterization of structural evolution and electrochemical performance.
• Fabrication and testing of a 21700 cylindrical-type cell using SiMg$_{y}$O$_{x}$ anodes.

Main Results:

• SiMg$_{y}$O$_{x}$ microparticles exhibit stable structural evolution and reduced internal cracks due to a magnesium silicate bonding network.
• The anode demonstrates high reversible capacities, stable cycling performance, and low electrode expansion.
• A 21700 cell achieved a 1000-cycle operation life, meeting practical requirements for electric vehicles and consumer electronics.

Conclusions:

• Magnesium doping effectively stabilizes the structure of micrometer-sized SiO$_{x}$ anodes against electrochemical stress.
• SiMg$_{y}$O$_{x}$ offers a promising solution for high-performance, long-lasting lithium-ion batteries.
• This structural design approach is valuable for developing next-generation alloying anode materials.