Robust Metallic Lithium Anode Protection by the Molecular‐Layer‐Deposition Technique

Abstract

Abstract The Li metal anode is considered as a promising alternative candidate for next‐generation Li metal batteries with high specific capacity, low potential, and light weight. However, the crucial problem for the Li metal anode is one of the biggest challenges. Mossy or dendritic growth of Li occurs in the repetitive Li stripping/plating process with an unstable solid electrolyte interphase (SEI) layer of nonuniform ionic flux, which can not only lead to low Coulombic efficiency, but can also create the risk of a short‐circuit, resulting in possible burning or explosion. Here, an advanced molecular‐layer‐deposition (MLD) Alucone protective layer is first demonstrated for Li metal anodes. By protecting Li foil with a controllable Alucone layer, the dendrites and mossy Li formation are effectively suppressed and the lifetime is significantly improved in different electrolytes (carbonate‐based and ether‐based). Furthermore, the detailed surface changes are studied by the advanced characterization technique of Rutherford backscattering spectrometry. The novel design of the MLD‐protected Li metal anode may bring in new opportunities to the realization of the next‐generation high‐energy‐density Li metal batteries.