Molecular Engineering Chemical Pre‐lithiation Reagent with Low Redox Potential for Graphite Anode Enables High Coulombic Efficiency

Abstract

Graphite (Gr) is a low‐cost and high‐stability anode for lithium‐ion batteries (LIBs). However, Gr anode exhibits an obstinate drawback of low initial Coulombic efficiency (ICE), owing to the active lithium loss for the solid electrolyte interphase (SEI) layer. Herein, a straightforward and effective chemical pre‐lithiation strategy is proposed to compensate for the lithium loss. A molecular engineering phenanthrene‐based lithium‐arene complex (Ph‐based LAC) reagent is designed by density functional theory (DFT) calculations. The engineering Ph‐based reagent enhances the stability of the π‐electron system and the electron‐donating capacity, resulting in a reduced redox potential to facilitate lithium transfer. The electrochemical distinct of the Ph‐based reagent is illustrated, the prelithiation process in a low Li‐insertion platform, and the lithiation degree is controllable with the dipping time (ICE = 102%, 3 min). Notably, a denser and homogeneous SEI layer has pre‐formed to enhance the Li+ transport and interface stability. Moreover, the lithium‐ion full batteries assemble with LiFePO4 and NCM811 cathode, which exhibits high ICE (96.5% and 90.3%) and energy density (310 and 333 Wh kg−1). These findings present a facile and controllable pre‐lithiation strategy to compensate for the lithium of LIBs, providing new valuable insights into the design and optimization of battery manufacture.