Fluorobenzosilane additive derived low-impedance SEI enables high-rate capacity of graphite anode

TPS containing -F/-Si bifunctional group exhibits superior film-forming capability. • A thin and uniform SEI film rich in LiF and Li x PO y F z is formed on graphite surface. • TPS-derived SEI film shows low impedance and high-temperature structural stability. • Li/graphite cell with TPS yields improved high-rate capacity and cyclic stability. As a mainstream anode material for lithium-ion batteries (LIBs), graphite suffers from undesirable interfacial reactions that damage its layered structure due to insufficient stability of solid electrolyte interphase (SEI) during prolonged lithiation/delithiation processes. To overcome the challenges associated with graphite-based LIBs, forming a stable SEI film through film-forming additives has emerged as a preferred optimization strategy. In this work, the triethoxy(pentafluorophenyl)silane (TPS) additive, enriched with -F/-Si dual functional groups, significantly enhances both the high-rate capacity and cyclic stability of graphite batteries. Addition of 1 wt% TPS boosts the rate capacity and cyclic stability of assembled batteries. Notably, the specific charge capacity of Li/graphite battery at 2 C rate increased from 81.9 mAh g⁻ 1 in baseline to 158.8 mAh g⁻ 1 , with a capacity retention of 98.7% after 250 cycles at 0.2 C, far exceeding the 61.4% of baseline system. Theoretical calculations and experimental results indicate that TPS preferentially adsorbs and reduces on graphite surface to construct a low-impedance organic/inorganic composite SEI film, suppressing electrolyte decomposition, accelerating Li + kinetics, and preserving electrode integrity. This study provides a novel approach for the precise design of interface for commercial graphite anodes by developing simple and efficient electrolyte film-forming additives, thereby offering technical and theoretical support for the sustainable application of long-life graphite-based batteries. Download: Download high-res image (241KB) Download: Download full-size image