Dynamic Ion‐Adsorption Interface for Uniform Lithium‐Ion Transport in High‐Performance Lithium Metal Batteries

The realization of high‐energy‐density lithium‐metal batteries is severely impeded by uncontrolled lithium‐ion transport and dendrite growth upon cycling, especially under high areal capacities and high current densities. Herein, we develop a dynamic ion‐adsorption poly‐4‐vinylpyridine (PP) interface to regulate lithium deposition for dendrite‐free lithium metal batteries. The PP interlayer electrochemically passivates the lithium metal surface during cycling, suppressing side reactions and promoting a stable lithium‐electrolyte interface. Meanwhile, the pyridinic nitrogen in PP provides abundant lithium‐ion adsorption sites, homogenizing ion distribution and regulating transport, which significantly enhances interfacial transport kinetics and enables dense lithium deposition under harsh conditions (high areal capacity ≥ 4 mAh cm −2 , and high current density ≥ 5 mA cm −2 ). As a result, Li||PP‐Cu asymmetric cells with lean electrolyte deliver a high average Coulombic efficiency of 99.33% at 8 mAh cm −2 . Impressively, PP‐Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 cells, paired with a high‐areal‐capacity cathode (4 mAh cm −2 ) and ultra‐thin lithium (20 µm), exhibit excellent cycling stability (0.13% decay/cycle) under lean electrolyte (10 µL mAh −1 ) conditions.