Dipole‐Engineered Conductive Additives for Ultrastable Interphase Evolution in High‐Areal‐Capacity Silicon Anodes

ABSTRACT Ensuring electrical integrity and interfacial stability in silicon (Si) anodes critically relies on conductive carbon additives; however, their potential role in modulating interphase evolution has rarely been systematically considered, and the mechanistic interplay between additive functionality and electrolyte chemistry remains insufficiently understood, thereby limiting the realization of high‐areal‐capacity operation. Here, a dipole‐engineered molecular design of an ionically/electronically conductive sulfonated carbon nanofiber (SC) additive is introduced, which establishes sulfonyl dipole‐mediated interfacial domains that preferentially direct fluoroethylene carbonate reduction toward the formation of a compact and LiF‐rich interphase. Incorporation of sulfonic acid functionalities enables robust hydrogen bonding with Si, promoting a spatially homogeneous electrode architecture with intimate interfacial contact and efficient charge percolation pathways that accelerate lithiation/delithiation dynamics. As a result, the Si–SC anode achieves an ultrahigh‐areal‐capacity of 10.2 mAh cm −2 and delivers 1784 mAh g −1 at a high current density of 10 A g −1 , while maintaining 94.2% capacity over 300 cycles at 1 A g −1 . Full‐cell evaluation with Ni‐rich layered cathodes further demonstrates stable capacity retention, underscoring practical applicability. This work introduces dipole‐directed conductive additive engineering as a new guiding paradigm that redefines them as chemically active interphase regulators for scalable, high‐energy‐density Si‐based next‐generation lithium‐ion batteries.