Regulating Solvation Dynamics and Lithium Plating via Ti ₃ C ₂ T _x ‐Engineered PVDF‐HFP Separators

Abstract The practical application of lithium metal batteries (LMBs) is hindered by uncontrolled Li dendrite growth and poor interfacial stability. Here, a functional separator composed of Ti ₃ C ₂ T _x MXene and PVDF‐HFP (MX/P‐H) is designed to suppress dendrite growth and enhance interfacial stability by regulating the Li ⁺ flux. The synergistic dipole interactions between Li ⁺ and the polar groups on the MXene (─O, ─OH, ─F) and PVDF‐HFP (─CF ₃ ) enhance Li ⁺ transport kinetics and block anion migration, ultimately stabilizing the Li/electrolyte interface. Theoretical calculations, coupled with experimental results, elucidate that the mechanism behind the formation of a stable LiF‐rich solid electrolyte interface (SEI) layer is driven by the effective reduction of TFSI ⁻ anions, enabled by the strong orbital hybridization. Enhanced interfacial stability promotes smooth and uniform Li deposition without dendrite growth, a behavior that is clearly visualized in symmetric cells via in situ optical analysis. Consequently, the MX/P‐H separator enables stable cycling for over 3800 h in Li||Li symmetric cells while maintaining 97.3% capacity retention over 1000 cycles in Li||LFP full cells. By integrating material functionality and interfacial regulation within a single separator design, this study provides a comprehensive approach to overcoming key limitations of Li metal anodes.