Eco-Friendly Water-Processable Polyimide Binders with High Adhesion to Silicon Anodes for Lithium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon anodes offer high theoretical energy density for lithium-ion batteries (LIBs).
• Significant volume expansion during lithiation causes mechanical degradation and limits commercialization of silicon anodes.
• Developing robust binders is crucial for stable silicon-based LIBs.

Purpose of the Study:

• To develop an eco-friendly, water-soluble binder for silicon anodes.
• To improve the mechanical stability and electrochemical performance of silicon anodes in LIBs.
• To address the volume expansion challenge in silicon anodes.

Main Methods:

• Synthesis of a water-soluble polyimide precursor (W-PAmAS) using water as a solvent.
• Fabrication of composite Si electrodes using low-temperature processing (150 °C).
• Incorporation of 3,5-diaminobenzoic acid to enhance binder-Si nanoparticle interaction via carboxylic acid groups.

Main Results:

• The W-PI binder chemically bonds silicon nanoparticles (SiNPs) through ester linkages, mitigating volume changes.
• The Si anode with W-PI binder demonstrated a high capacity of 2061 mAh g^-1.
• Excellent cyclability was achieved, retaining 1883 mAh g^-1 after 200 cycles at 1200 mA g^-1.

Conclusions:

• The developed water-soluble polyimide (W-PI) is a highly effective binder for silicon anodes.
• This binder significantly enhances the electrochemical performance and stability of high-capacity LIBs.
• The eco-friendly synthesis and processing offer a promising route for commercializing silicon anodes.