Separators Based on the Dynamic Tip‐Occupying Electrostatic Shield Effect for Dendrite‐Free Lithium‐Metal Batteries

Abstract Lithium‐metal batteries (LMBs) have long been considered the “holy grail” of next‐generation energy storage systems due to the unique advantages of Li metal, such as having a high specific capacity and the lowest potential. Unfortunately, the practical application of LMBs is seriously hindered by the uncontrollable growth of dendritic Li. To address this issue, a positively charged layer (PCL) with freely moving multication sidechains is successfully polymerized on a commercial polypropylene (PP) separator. The cationic groups on the sidechains of the polymer realize dendrite‐free Li deposition based on the “dynamic tip‐occupying electrostatic shield” effect. LMBs with improved cycling stability and rate performance can be achieved by using a PP‐N,N,N,N”,N”‐pentamethyldiethylenetriamine (PP‐PMDT) separator. All the results demonstrate that this strategy for constructing a flexible “electrostatic shield layer” can successfully eliminate the formation of Li dendrites while retaining the desired performance.