A Conversion Aluminum Fluoride Nanowire Interlayer for Stable Lithium Metal Batteries

The use of a lithium metal anode enables batteries with significantly higher energy density, but at the expense of the growth of lithium dendrites that trigger internal short circuits, induce safety risks, and reduce cycle stability. To address this challenge, here, we report the design of an aluminum fluoride nanowire membrane as a conversion interlayer to regulate lithium deposition for significantly more stable and safe lithium metal batteries. The interlayer generates a LiF-rich solid electrolyte interphase and alloy nanoparticles in contact with lithium to offer active sites guiding lithium nucleation, regulating lithium deposition, and increasing Coulombic efficiencies. With such an interlayer, lithium metal full cells show significantly improved stability compared to those with bare Cu, when paired with a LiFePO₄ or LiNi_0.8Co_0.1Mn_0.1O₂ cathode. Our results indicate that using an aluminum fluoride interlayer can be a promising strategy in realizing lithium metal batteries with high specific energy density.