Poly(ethylene-alt-maleic acid)-Based Binders for Silicon Anodes

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• High-energy-density lithium-ion batteries (LIBs) are crucial for electric vehicles and electronics.
• Silicon-rich anodes offer high theoretical capacity but suffer from volumetric expansion during cycling.
• Ionically conductive binders can improve the stability and cyclability of silicon anodes.

Purpose of the Study:

• To synthesize and evaluate water-soluble binders for silicon anodes.
• To investigate the effect of polyether side chain functionalization and hydrolysis ratio on binder properties.
• To assess the electrochemical performance and processability of silicon anodes using these novel binders.

Main Methods:

• Synthesis of six binders by functionalizing poly(ethylene-alt-maleic anhydride) (PEaMAn) with polyether side chains and varying hydrolysis.
• Characterization of synthesized binders.
• Electrochemical performance evaluation in half-cells, including capacity, cycling stability, and rate performance.

Main Results:

• Polyether-functionalized binders reduced slurry viscosity, improving electrode processability.
• These binders exhibited poor adhesion to the current collector and faster impedance increase.
• The fully hydrolyzed poly(ethylene-alt-maleic acid) (PEaMAc) binder demonstrated strong adhesion and superior electrochemical performance.
• PEaMAc achieved an initial Coulombic efficiency of 71.3% and high delithiation capacities (2230 mAh g-1 at C/10, 1190 mAh g-1 at 1C).
• PEaMAc showed better rate performance than the conventional LiPAA binder.

Conclusions:

• The fully hydrolyzed PEaMAc binder is a promising candidate for silicon anodes in LIBs.
• Binder design significantly impacts electrode processability, adhesion, and electrochemical performance.
• Optimized binder selection is critical for advancing silicon anode technology in energy storage applications.