A multifunctional binder with gallic acid-Regulated crosslinking and interface for high-capacity silicon anodes

The massive expansion of silicon anodes during cycling is a challenge that collapses the electrode structure and severely reduces interfacial stability, ultimately shortening battery life significantly. To address these issues, we have utilized gallic acid (GA) to endow sodium alginate (SA) with enhanced properties and designed a multifunctional binder (SG91) capable of inducing the establishment of a functional solid electrolyte interface (SEI) membrane. Significantly, adjusting the dosage of GA has resulted in a substantial boost in the electrode's ionic/electron transport capability and structural integrity. Results clearly show that an appropriate amount of GA not only facilitates the creation of a fluorine-enriched solid-electrolyte interphase but also remarkably accelerates ionic and electronic transport. Based on this, the Si@SG91 electrode maintains 1751 mAh/g even after 500 cycles at 1.6 A/g. The introduction of GA can also effectively enhance the hydrophilicity of conductive carbon black in pure water and reduce the parasitic reactions occurring at the electrode-electrolyte junction. This study fully demonstrates GA's outstanding potential during the research and creation process of silicon-based anode binders applicable to lithium-ion batteries.