A Melt-Infused Li-Sn Alloy Anode with an Iodine-Rich Interface for Long-Life and High-Rate Lithium Metal Batteries

Lithium metal anodes (LMAs) are severely limited by interfacial instability, dendritic lithium growth, and polysulfide-induced corrosion, which collectively impede their practical application in high-energy rechargeable batteries. Herein, we report a carbon cloth-supported Li-Sn alloy anode with an iodine-rich interfacial layer via a facile melt-infusion strategy (denoted as LSC). Owing to the intrinsic lithiophilicity of the Li-Sn alloy framework and the formation of an iodine-rich solid electrolyte interphase (SEI), the LSC anode exhibits significantly reduced lithium nucleation overpotential, accelerated redox kinetics, and highly uniform lithium deposition behavior. In addition, the iodine-rich SEI effectively suppresses parasitic reactions between lithium metal and soluble polysulfides, endowing the LSC anode with superior corrosion resistance and interfacial stability. Consequently, when paired with a sulfur cathode at room temperature (25 °C), the LSC anode enables stable cycling over 1400 cycles at 2 C with an ultralow capacity decay rate of 0.041% per cycle. Moreover, in lithium iron phosphate (LFP) full cells tested at 25 °C, the LSC anode maintains excellent durability for more than 600 cycles at 15 C with a high capacity retention of 96.69%. This work demonstrates a synergistic strategy integrating alloy regulation and halogen-rich interfacial engineering to address the fundamental challenges of lithium metal anodes, providing a scalable and effective pathway toward high-rate and long-life lithium metal batteries.