A cycling robust network binder for high performance Si-based negative electrodes for lithium-ion batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon offers high capacity for next-generation lithium-ion batteries but suffers from capacity fading due to volume changes during cycling.
• Effective binders are crucial to mitigate these volume changes and improve electrode stability.

Purpose of the Study:

• To develop a novel self-healing composite binder for silicon-based negative electrodes.
• To enhance the electrochemical performance and cycling stability of lithium-ion batteries utilizing silicon anodes.

Main Methods:

• A composite binder of carboxymethyl cellulose (CMC) and cationic polyacrylamides (CPAM) was synthesized and characterized.
• The binder's self-healing properties were evaluated through its reversible electrostatic cross-linking mechanism.
• Electrochemical performance was tested using silicon-based electrodes with the CMC-CPAM binder in lithium-ion battery configurations.

Main Results:

• The CMC-CPAM binder demonstrated excellent mechanical strength and adhesion, effectively accommodating silicon's volume expansion.
• Electrodes with the self-healing binder exhibited superior cycling stability compared to conventional CMC-PAA and linear CMC binders.
• A capacity of 1906.4 mAh·g^-1 was retained after 100 cycles, and 78% capacity was maintained after 350 cycles at high mass loading (~4 mg·cm^-2).

Conclusions:

• The self-healing CMC-CPAM composite binder is a promising solution for overcoming the limitations of silicon anodes in lithium-ion batteries.
• This novel binder architecture significantly enhances the long-term cycling performance and durability of high-capacity silicon electrodes.