• A single-layer graphdiyne on MXene (sGDY@MXene) heterostructure integrated into polypropylene separators directs a LiF-rich solid electrolyte interphase and long-term stability of lithium-metal anodes.
• Instead of direct electron transfer from surface polar groups to fluorinated anions, adsorbed Li ions on sGDY@MXene act as dynamic bridges collaboratively connecting the electron-donating heterostructure to the anion and its derivatives, facilitating interface charge transfer.
• The dedicated balance between lithiophilicity and high Li-ion mobility is key to promoting dipole-induced fluorinated-anion decomposition.
• This work provides new insights into the design of functional separators for high-performance lithium-metal batteries.