Silicon monoxide (SiOx) is a promising anode material for lithium-ion batteries owing to its high theoretical capacity, yet its application is limited by low initial Coulombic efficiency (ICE) caused by irreversible lithium consumption. Prelithiation is an effective strategy to address this issue, although the influence of binder chemistry during prelithiation has not been systematically clarified. In this work, the effects of binder formulation and prelithiation strategy on SiOx anodes are investigated by comparing five binder systems under direct-contact prelithiation (DCP) and chemical prelithiation (CP). Electrochemical results show that binder engineering strongly impacts lithiation efficiency, reversible capacity, and cycling stability. Among all systems, electrodes employing the PAA+SBR binder consistently deliver the best performance, achieving high ICE (>95%), high reversible capacity (up to ~1900 mAh g−1), and stable capacity retention over extended cycling under both DCP and CP. Morphological and interfacial analyses reveal that PAA+SBR effectively suppresses electrode cracking, limits thickness expansion, and maintains low interfacial impedance. X-ray photoelectron spectroscopy further indicates that PAA+SBR forms a relatively thinner, inorganic-rich interphase dominated by Li2CO3 and Li2O, in contrast to the organic and silicate-rich interphase observed for PAA+CMC. These findings demonstrate that binder engineering plays a critical role in enabling high-performance prelithiated SiOx anodes.
Silicon is one of the most promising anode materials for next-generation lithium-ion batteries because of its very high theoretical capacity and natural abundance, yet its practical use is limited by severe volume expansion, structural degradation, unstable solid electrolyte interphase formation, and capacity fading. Beyond these known issues, a critical but underexplored degradation feature is the Coulombic efficiency trough, a transient but universal dip in efficiency that appears during early-to-mid cycling. This trough is generally associated with silicon volume change that generates sponge-like porous structures, repeated interfacial rupture, continued SEI renewal, and irreversible lithium loss. This review analyzes the mechanistic origin of the CE trough and highlights it as a diagnostic framework that links the fundamental cause of volume change to consequences that include new surface generation, interfacial instability, and declining lithium inventory. We also evaluate major suppression strategies, including LiF-rich SEI formation through electrolyte design, mechanically adaptive binders that accommodate expansion, and voltage window optimization to limit interfacial stress. Together these approaches reduce irreversible reactions, stabilize the SEI, and improve cycling stability. Treating the CE trough as a quantitative performance indicator provides a unified basis for comparing mitigation strategies and advancing durable, high-capacity silicon anodes.
