Tuning the Li–Sn alloy dispersity to improve the lithiophilicity of lithium metal anodes towards stable lithium metal batteries

Abstract

Constructing lithium alloy composite anodes is a crucial approach to achieving high-energy-density lithium metal batteries with long cycling stability. However, achieving a uniform distribution of lithium alloy within the anodes using the current methods is challenging. In this study, we fabricated a novel composite lithium anode, p-20Li/Li₁₃Sn₅, by incorporating metallic lithium and tin powder using a straightforward “roll and fold” technique. This method ensured the uniform distribution of Li₁₃Sn₅ particles within the lithium matrix, thereby enhancing the lithiophilicity of the composite electrode. The unique structural characteristics of the p-20Li/Li₁₃Sn₅ anode lead to significantly improved performances. Compared to the lithium alloy anode prepared using tin foil (f-20Li/Li₁₃Sn₅), the p-20Li/Li₁₃Sn₅ anode exhibited a stable voltage response and reduced interfacial impedance in symmetric cells over 400 hours of cycling. When paired with a high-capacity sulfurized polyacrylonitrile (SPAN) cathode (5.6 mA h cm⁻²), the cell using p-20Li/Li₁₃Sn₅ as the anode displayed superior cycling stability, achieving 91.5% capacity retention over 100 cycles. This innovative approach, which leverages lithiophilic metal powders to build highly dispersed lithium alloy networks, presents a promising strategy for the advancement of lithium metal batteries. Our findings could contribute to the development of composite lithium alloy anodes with high lithium alloy utilization, paving the way for next-generation lithium battery technologies.