Improving the Durability of Lithium-Metal Anode via In situ Constructed Multilayer SEI

In this work, a novel multilayer solid electrolyte interphase (SEI) is demonstrated to prolong the durability of a lithium-metal anode. It is in situ generated via reducing lithium bis(oxalate) borate (LiBOB) and fluoroethylene carbonate (FEC) in the electrolyte containing them as additives. The as-obtained SEI could be roughly divided into three layers: the polycarbonates surface membrane, LiF-rich middle layer, and B-containing polymer bottom film corresponding to their sequentially reductive potentials of 0.8, 1.55, and 1.8 V vs Li⁺/Li, respectively. This special structure prolongs the durability of lithium-metal anode since the elastic bottom layer could buffer the influence of volumetric variation and the LiF-rich middle layer could suppress Li dendrite growth and electrolyte permeation. Benefiting from the protection of this multilayer SEI, LiNi_0.88Co_0.09Al_0.03O₂/Li batteries with ultrahigh cathode loading of ∼4.5 mAh cm^-2 stably operate for 200 cycles with the accumulated capacity of 750 mAh cm^-2 and the coulombic efficiency of 99.78%. This approach provides a simple and efficient strategy to hover lithium-metal anode.