Reaction-Programmed Interphase Reconstruction by an Ultrathin Zinc Phosphate Nanofilm for Reversible Lithium Metal Anodes

Abstract An ultrathin zinc phosphate nanofilm is reported as a reaction-programmed precursor that reconstructs during initial Li plating. Fabricated by ion-layer epitaxy at the air/water interface, the nanofilm uniformly covers Cu with a thickness of 24 nm. Upon lithiation, zinc phosphate converts into metallic Zn and a Li3PO4-rich phase. The in situ-formed Zn subsequently alloys with Li, creating lithiophilic sites that reduce the nucleation barrier and promote uniform deposition, while the phosphate-rich phase suppresses side reactions and stabilizes the interphase. This reconstruction integrates nucleation regulation and interphase protection within a single precursor layer. Consequently, modified Cu exhibits a reduced nucleation overpotential, a transition from progressive to instantaneous nucleation, and compact Li deposition. Li plating/stripping cells operate stably over 1400 h, while LiFePO4, NCM811, and sulfur full cells show improved rate capability and cycling durability.