Zwitterionic Polymer Binder Networks with Structural Locking and Ionic Regulation Functions for High Performance...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Silicon anodes offer high theoretical capacity but face challenges like volume expansion and poor conductivity.
• Existing binders struggle to provide the necessary mechanical support and ionic conductivity for silicon anodes.
• Developing advanced binders is crucial for realizing high-performance lithium-ion batteries.

Purpose of the Study:

• To design and synthesize a multifunctional binder, PAA-p(HEA-SBMA), for silicon anodes.
• To investigate the binder's ability to address silicon anode limitations such as volume expansion and cycling stability.
• To evaluate the electrochemical performance and long-term cycling stability of silicon anodes using the novel binder.

Main Methods:

• In situ thermal cross-linking method for binder preparation.
• Characterization of binder properties including mechanical strength and ionic conductivity.
• Electrochemical testing of silicon anodes with the PAA-p(HEA-SBMA) binder, including cycling performance and capacity retention.

Main Results:

• The PAA-p(HEA-SBMA) binder demonstrated excellent mechanical properties through synergistic covalent, hydrogen, and ionic interactions.
• The binder facilitated improved lithium-ion transport and lithium salt dissociation, leading to a stable solid electrolyte interphase (SEI).
• Silicon anodes with the PAA-p(HEA-SBMA) binder achieved a discharge capacity of 981.63 mAh g⁻¹ after 1000 cycles at 0.5 C.

Conclusions:

• The PAA-p(HEA-SBMA) binder effectively mitigates silicon anode degradation through structural locking and dynamic ionic regulation.
• This multifunctional binder design significantly enhances the long-term cycling performance of silicon anodes.
• The study provides valuable insights for developing advanced binders for high energy density lithium-ion batteries.