Developing a “Water‐Defendable” and “Dendrite‐Free” Lithium‐Metal Anode Using a Simple and Promising GeCl₄ Pretreatment Method

Abstract

Lithium metal is an ultimate anode in "next-generation" rechargeable batteries, such as Li-sulfur batteries and Li-air (Li-O₂ ) batteries. However, uncontrollable dendritic Li growth and water attack have prevented its practical applications, especially for open-system Li-O₂ batteries. Here, it is reported that the issues can be addressed via the facile process of immersing the Li metal in organic GeCl₄ -THF steam for several minutes before battery assembly. This creates a 1.5 µm thick protection layer composed of Ge, GeO_x , Li₂ CO₃ , LiOH, LiCl, and Li₂ O on Li surface that allows stable cycling of Li electrodes both in Li-symmetrical cells and Li-O₂ cells, especially in "moist" electrolytes (with 1000-10 000 ppm H₂ O) and humid O₂ atmosphere (relative humidity (RH) of 45%). This work illustrates a simple and effective way for the unfettered development of Li-metal-based batteries.