Regulating Lithium Deposition Behaviors by Functional PVDF‐HFP/NaTi2(PO4)3 Composite Separator

Abstract The unpredictable growth of lithium (Li) dendrite is one of the crux issues in the commercial application of the Li‐metal batteries (LMBs). Herein, a flexible PVDF‐HFP/LiClO 4 /NaTi 2 (PO 4 ) 3 (NTP) layer modified polypropylene (PP) separators are designed to achieve homogeneous nucleation and growth of Li. The introduction of NTP particles not only reduces the crystallinity of the polymer but also generates a rapid Li + migration pathway at the interface, which is conducive to regulating the Li + flux and guiding the uniform Li deposition by improving ionic conductivity. In addition, because of the high electrolyte wettability and the enhanced mechanical strength of the functionalized separator, the mass transport capability is promoted and the penetration of Li dendrite can be avoided. Consequently, the modified separators with 20 wt% NTP (PP@PHNTP‐20) endow Cu||Li batteries with an excellent average Coulombic efficiency of ≈99%. Furthermore, the long‐term reversible Li plating/stripping can be achieved in the Li symmetric battery, and the LiFePO 4 (LFP) ||Li batteries with PP@PHNTP‐20 present high capacity retention and improved C‐rate performance in a carbonate‐based electrolyte without additives.