Self-Repairable Silicon Anodes Using a Multifunctional Binder for High-Performance Lithium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon anodes offer high theoretical capacity but suffer from electrode degradation due to large volume changes during cycling.
• Pulverization and delamination of silicon anodes limit their practical application in high-performance batteries.

Purpose of the Study:

• To design and synthesize a self-healable and stretchable binder for silicon anodes.
• To improve the structural integrity and electrochemical performance of silicon anodes.

Main Methods:

• Development of a multifunctional binder: polydioxythiophene:polyacrylic acid:phytic acid (PEDOT:PAA:PA, PDPP).
• Fabrication of silicon anodes utilizing the self-healing binder.
• Electrochemical testing to evaluate cycling stability, capacity retention, and rate capability.
• Demonstration of autonomous crack self-healing under practical battery operating conditions.

Main Results:

• The self-healing binder (PDPP) effectively repairs cracks and damages in silicon anodes during cycling.
• Silicon anodes with the PDPP binder achieved a reversible capacity of 2312 mAh g^-1 after 100 cycles with 94% initial Coulombic efficiency.
• The binder enhanced Li-ion diffusivity and electronic conductivity, leading to excellent rate capability (2084 mAh g^-1 at 5 C).
• Autonomous self-healing of artificially created cracks was demonstrated under operational conditions.

Conclusions:

• The developed self-healing binder provides silicon anodes with exceptional structural integrity and self-repair capabilities.
• This approach significantly overcomes the limitations of silicon anodes, offering superior performance compared to existing technologies.
• The self-healing binder holds great promise for advancing high-capacity, long-lasting silicon-based batteries.