Cross‐Linking Surface Chemistry Regulation by an Ionic Complex Anchored Interlayer for Stable Li Metal Batteries

Lithium (Li) metal batteries (LMBs) using a Li anode and nickel (Ni)‐rich cathode constitute a promising powering solution for long‐range electric vehicles. Unfortunately, both the Li anode and Ni‐rich cathode suffer from surface deterioration‐related failures. Herein, an ionic complex‐anchored interlayer consisting of positively charged skeletons with conjugated π bonds, Li + ions, and functional anions is investigated to trigger a cross‐linked surface chemistry regulation in LMBs. It is revealed that the Li + and anions electrostatically anchored on the interlayer can be released to alter the crossover electrochemistry of LMB for durable electrode interphases. Furthermore, by presetting the interlayer on a carbonaceous scaffold, an extended delocalization path of π electrons enables uniform adsorption of the anions, while the prelithiated carbon scaffold by Li + from the interlayer facilitates the anion decomposition to form a robust bilayer surface, affording reversible Li plating/stripping with high average coulombic efficiency beyond 99.5% over 500 cycles. Simultaneously, the modified cathode interphase withstands structural stability of the Ni‐rich materials and mitigates current collector corrosion efficiently. These merits lead to significantly enhanced performance of LMBs, where stable cycling over 150 cycles is achieved for an anode‐free pouch cell with a high cathode loading of 6 mAh cm −2 .