In-situ constructing LiF-rich lithiophilic interface by unifying additive approach and electrochemical treatment for AFLMBs

Abstract

Anode-free Li metal batteries (AFLMBs) are considered as the ultimate high-energy density batteries. However, the lithiophobic nature of the bare current collector (CC) and the instability of the solid electrolyte interphase (SEI) layer lead to the formation of lithium dendrites, causing severe capacity fading. Herein, we propose a novel method that combines an additive approach with in-situ electrochemical treatment to stabilize AFLMBs. LiSbF6 was selected as a functional additive for the LHCE electrolyte to achieve lithiophilic treatment of the CC surface and a LiF-rich SEI layer. By applying a constant potential (V-hold) before cycling in the AFLMB configuration, the LiSbF6 additive undergoes preferential reduction to form lithiophilic Sb nanoparticle arrays and a LiF-rich SEI layer on the Cu CC. Benefiting from lithiophilic and LiF-rich interfacial layer, Cu/LFP cells using the LiSbF6 additive with V-hold (Sb-Vhold) show lower SEI resistance and charge-transfer resistance, and exhibit lower nucleation overpotential than the bare sample (N). The enhanced properties of the CC in Sb-Vhold mitigate lithium dendrite growth and reduce dead lithium formation during cycling. As a result, Sb-Vhold demonstrated improved Coulombic efficiency in the Li/Cu half-cells, and showed enhanced capacity retention and rate capability in Li@Cu/LFP LMBs and Cu/LFP AFLMBs. © 2025 Elsevier B.V.