Bollard-Anchored Binder System for High-Loading Cathodes Fabricated via Dry Electrode Process for Li-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Manufacturing

Background:

• Dry battery electrode (DBE) processing offers environmental and cost benefits over wet-coating methods.
• Current DBE fabrication relies on polytetrafluoroethylene (PTFE), facing regulatory scrutiny (PFAS) and performance limitations.
• PTFE's limitations include restricted Li-ion conductivity, poor elastomeric properties, and inadequate particle adhesion.

Purpose of the Study:

• To develop a novel, PTFE-less binder system for dry battery electrode fabrication.
• To overcome the limitations of PTFE in DBE processing, including regulatory concerns and performance constraints.
• To enhance the ionic conductivity, mechanical strength, and overall performance of high-mass loading cathodes.

Main Methods:

• Exploration of a dual-binder system, the "bollard hitch" model, using poly(acrylic acid)-grafted sodium carboxymethyl cellulose (PC) as a "bollard" and PTFE as an "anchor."
• Significant reduction of PTFE content (over 70%) in the binder formulation.
• Fabrication of high-mass loading cathodes (up to 90 mg cm^{- 2}, 15.6 mAh cm^{- 2}).

Main Results:

• Successful implementation of the first PTFE-less binder system for binder fibrillation in DBE.
• Demonstrated reduction in PTFE usage by over 70% while maintaining or improving electrode performance.
• Achieved high-mass loading cathodes with enhanced ionic conductivity and mechanical strength.
• Validated suitability for high-voltage applications.

Conclusions:

• The novel dual-binder system effectively replaces PTFE in DBE fabrication, addressing regulatory and performance issues.
• This approach enables the production of high-performance, durable energy storage systems with improved sustainability.
• The "bollard hitch" model shows significant potential to revolutionize manufacturing processes for advanced batteries.