Electrode-Side Catalytic Regulation Directs Electrolyte Decomposition for Stable Silicon Anodes.

Abstract

The electrochemical stability of silicon anodes is critically influenced by the initial decomposition pathways of fluorine-containing electrolyte species, which dictate the solid electrolyte interphase (SEI) composition and stability. However, existing strategies primarily rely on electrolyte fluorination or artificial interphases to indirectly regulate SEI chemistry, whereas precise electrode-side regulation of fluorine-containing electrolyte decomposition remains challenging. Herein, a binder-free Co SACs-Si-N/C electrode is developed to direct interfacial reactions through single-atom catalysis. Atomically dispersed Co-N4 sites selectively strengthen PF6- adsorption, modulate the interfacial electronic structure, and steer fluorine-containing electrolyte species toward preferential inorganic decomposition, thereby constructing a compact LiF-rich SEI that suppresses parasitic reactions and stabilizes the silicon/electrolyte interface. As a result, the Co SACs-Si-N/C electrode delivers a reversible capacity of 1128.8 mAh g-1 after 1200 cycles at 1.0 A g-1, while lithium cobalt oxide pouch cells further demonstrate their practical applicability. Machine learning established a quantitative correlation between electrochemical characterization parameters and performance evolution. This work reveals the critical role of electrode-regulated interfacial reaction pathways in governing SEI evolution and provides a catalytic strategy for developing durable silicon-based anodes.

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