Submicrometer Lithiophilic Interphase Layer Engineering toward Inorganic-Rich Solid Electrolyte Interphase for...

Anode-free lithium metal battery (AFLMB) is considered as a great candidate for traditional LMB with excessive Li metal in anode suffering from safety and energy density issues. However, direct use of bare copper (Cu) current collector with nonlithiophilic nature results in poor Li deposition and stripping behavior in AFLMB, which limits cycling stability in practical application. Building a thin lithiophilic interphase layer on the Cu current collector not only effectively addresses such issues but also minimizes energy density loss. Here, the modified Cu current collector, constructed by a submicrometer lithiophilic interphase layer (∼0.55 μm) based on silica nanospheres decorated with silver nanoparticles (Ag NPs) and polyacrylonitrile binder, enables a highly reversible Li deposition and stripping. The introduction of Ag NPs and formation of Si-O-Ag units on the silica nanospheres effectively enhance the lithiophilic feature of Cu substrate and promote Li⁺ transportation. The interphase layer also contributes to the formation of robust solid electrolyte interphase rich in inorganic LiF and Li₃N. High Coulombic efficiency (CEs) of 98.5% for 650 cycles are achieved in half cells. Moreover, anode-free pouch-type full cell with high-loading lithium iron phosphate as cathode shows significantly improved cycling stability with high average CEs over 99.3% for 100 cycles. This work provides a simple and scalable way for the development of submicrometer lithiophilic interphase layer engineering for high-performance AFLMB.