Chemically Coupled Multifunctional Binder Networks Enable Stable and Safe Microscale Silicon Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Silicon anodes offer high energy density for lithium-ion batteries.
• Volume expansion during cycling causes capacity fading and limits silicon anode application.
• Improving thermal safety is crucial for next-generation batteries.

Purpose of the Study:

• To develop a novel flame-retardant, stretchable binder for microscale silicon anodes.
• To enhance the electrochemical performance and thermal safety of silicon-based anodes.
• To overcome the limitations of silicon anodes for practical battery applications.

Main Methods:

• Synthesized a multifunctional binder by chemically cross-linking poly(acrylic acid) (PAA) and adenosine triphosphate (ATP) via amidation.
• Fabricated microscale silicon (µSi) electrodes using the ATP-PAA binder.
• Evaluated electrochemical performance (Coulombic efficiency, cycling stability, specific capacity) and thermal safety.

Main Results:

• The µSi/ATP-PAA electrode achieved a high initial Coulombic efficiency of 89.33%.
• Excellent long-term cycling stability was observed, retaining 1427 mAh g^-1 after 500 cycles at 1.2 A g^-1.
• The phosphorus-rich ATP component significantly improved the thermal safety of the silicon-based electrodes.

Conclusions:

• The developed ATP-PAA binder effectively mitigates volume changes and enhances cycling stability of silicon anodes.
• The binder imparts flame-retardant properties, improving the overall safety of lithium-ion batteries.
• This strategy offers a practical approach for designing advanced binders for high-energy-density and safe Si-based anodes.