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_0.8Co_0.1Mn_0.1O₂ 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.