Cross-linked multifunctional binder in situ tuning solid electrolyte interface for silicon anodes in lithium ion...

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Silicon anodes offer high capacity for lithium-ion batteries but suffer from volume expansion during cycling.
• Effective binders are crucial for maintaining electrode integrity and mitigating silicon's performance degradation.

Purpose of the Study:

• To develop a novel, covalently crosslinked binder for silicon anodes.
• To improve the electrochemical performance and cycling stability of silicon-based lithium-ion batteries.

Main Methods:

• Citric acid (CA) and carboxymethyl cellulose (CMC) were used to create a covalently crosslinked CA@CMC binder via esterification.
• The Si@CA@CMC-1 electrode material was synthesized and tested for electrochemical performance.
• In situ electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) were employed to analyze the binder's effect on the solid electrolyte interphase (SEI).

Main Results:

• The Si@CA@CMC-1 electrode exhibited an initial coulombic efficiency (ICE) of 82.1%.
• After 510 cycles at 0.5 A/g, the specific capacity remained higher than that of commercial graphite.
• Ester bonds formed between the CA@CMC binder and silicon particles were attributed to the enhanced performance.

Conclusions:

• The CA@CMC binder effectively alleviates silicon volume expansion and improves electrode stability.
• The binder's ability to tune the SEI composition offers a new strategy for optimizing silicon anode performance.
• This approach presents a scalable method for developing high-performance silicon anodes for advanced lithium-ion batteries.