A Gradient Composite Structure Enables a Stable Microsized Silicon Suboxide-Based Anode for a High-Performance...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Microsized anodes in lithium-ion batteries suffer from volume expansion and capacity degradation.
• Silicon suboxide (SiO) is a promising anode material due to its high theoretical capacity.
• Structural instability limits the practical application of SiO-based anodes.

Purpose of the Study:

• To develop a stable and high-capacity microsized silicon suboxide anode.
• To mitigate volume changes and capacity fading in SiO anodes.
• To enhance the electrochemical performance of anodes for advanced lithium-ion batteries.

Main Methods:

• Fabrication of a gradient composite anode (d-SiO@SiO/C@C) with a microsized SiO core, SiO/C interlayer, and carbon outer layer.
• Utilizing a gradient composite strategy to manage stress and improve structural integrity.
• Electrochemical testing of the composite anode in a full cell with a high-nickel cathode.

Main Results:

• The d-SiO@SiO/C@C anode achieved a specific capacity of 1023 mAh/g after 300 cycles at 1 A/g with >90% retention.
• Demonstrated excellent cycling stability with an average Coulombic efficiency exceeding 99.7%.
• A full cell exhibited a specific energy density of 569 Wh/kg and robust cycling performance.

Conclusions:

• The gradient composite strategy effectively addresses the volume expansion and capacity fading issues in microsized SiO anodes.
• The fabricated d-SiO@SiO/C@C anode offers a promising solution for high-performance lithium-ion batteries.
• This approach provides a viable pathway for designing structurally stable and electrochemically robust microsized anodes.