Rational Molecular Design of Aryl-Lithium Reagent Enables Precise Chemical Prelithiation of Graphite Anodes for Achieving Ideal 100% Initial Coulombic Efficiency.

Prelithiation is a recognized strategy to enhance the initial Coulombic efficiency (ICE) and energy density of lithium-ion batteries (LIBs). However, existing methods generally suffer from insufficient lithiation precision, poor spatial homogeneity, and limited operational feasibility. Here, a molecular customized prelithiation reagent, 1-methyl-naphthalene-lithium/2-methyl tetrahydrofuran ( = 0.21 V vs Li/Li), is designed to lithiate graphite anode to its threshold potential for irreversible Li-storage ( = 0.22 V vs Li/Li), thereby achieving an ideal ICE of 100%. The well-matched potentials of and enable self-terminating prelithiation upon reaching equilibrium states, precisely eliminating irreversible lithium loss while avoiding the stringent control of lithium dosages or durations required by traditional methods. Combined microstructural and computational analyses reveal that the spontaneous formation of Stage-IV lithium-graphite intercalation compounds ( = 0.22 V) drives the growth of spatially uniform, inorganic-rich solid-electrolyte interphases (SEI) with accelerated Li transport kinetics. Full cells incorporating prelithiated electrodes demonstrate marked improvements in ICE, capacity retention, and energy density. In addition, the universality of this potential-matching approach is demonstrated for hard carbon and silicon/carbon anodes. Our work advances the understanding of graphite intercalation chemistry and provides a scalable, customizable approach to precise prelithiation in LIBs.