Harnessing Stiffness and Anticorrosion of Chromium in an Artificial SEI to Achieve a Longevous Lithium-Metal Anode

The safety risks brought by dendrite growth and volume changes keep investors away from commercial application, even lithium-metal material owns high energy density and low potential. The development of artificial solid electrolyte interphase (SEI) could not only solve the problems of inhomogeneity and fragility of native SEI film but also block electrochemical corrosion during long-Term rest and inhibit the notorious dendrite growth. Herein, a hybrid SEI film composed of a metal Cr and fast ion conductor, LiF, is in situ generated for the lithium-metal electrode. Based on the unique property of metal Cr of high elastic modulus, anticorrosion, and especially no alloy phase with lithium, the hybrid SEI film supported by a Cr framework exhibited high mechanical strength and stability, even in a high-current-density and large area capacity plating-stripping process. The galvanic corrosion test results showed that the corrosion current of a Cr-LiF hybrid SEI film-coated lithium-metal electrode decreased to 15 nA cm-2, only 1/15 of the bare lithium anode with native SEI. An enhanced electrochemical performance was achieved in terms of long cyclic stability at a large area capacity of 5 mA h cm-2 in symmetric cells and high capacity retention in Cr-LiF-Li || LiFePO4 full cells such as â 96.6% over 1000 cycles at 1C and â 90% over 600 cycles at 5C. Considering the moderately fabricated strategy, multiple stable mechanisms, and outstanding electrochemical performances, it is reasonable to apply this hybrid artificial SEI vastly in metal lithium batteries.