An In Situ Generated Organic/Inorganic Hybrid SEI Layer Enables Li Metal Anodes with Dendrite Suppression Ability, High‐Rate Capability, and Long‐Life Stability

Abstract High‐quality solid electrolyte interphase (SEI) layers can effectively suppress the growth of Li dendrites and improve the cycling stability of lithium metal batteries. Herein, 1‐(6‐bromohexanoyl)‐3‐butylurea is used to construct an organic/inorganic hybrid (designated as LiBr‐HBU) SEI layer that features a uniform and compact structure. The LiBr‐HBU SEI layer exhibits superior electrolyte wettability and air stability as well as strong attachment to Li foils. The LiBr‐HBU SEI layer achieves a Li + conductivity of 2.75 × 10 −4 S cm −1 , which is ≈50‐fold higher than the value measured for a native SEI layer. A Li//Li symmetric cell containing the LiBr‐HBU SEI layer exhibits markedly improved cyclability when compared with the cell containing a native SEI layer, especially at a high current density (e.g., cycling life up to 1333 h at 15 mA cm −2 ). The LiBr‐HBU SEI layer also improves the performance of lithium−sulfur cells, particularly the rate capability (548 mAh g −1 at 10 C) and cycling stability (513 mAh g −1 at 0.5 C after 500 cycles). The methodology described can be extended to the commercial processing of Li metal anodes as the artificial SEI layer also protects Li metal against corrosion.