Fabrication of Li-affinitive alloy protection layer for dendrite-free stable lithium metal electrode

Abstract

Inducing the stable planar lithium deposition is the key factor for commercializing lithium metal electrode for the next-generation battery system. Among them, Lithium alloys have been studied due to their intrinsic high $Li^+$ ion diffusivity. Thanks to their successful application, it became a clue to many studies on preventing dendritic lithium deposition. However, as repeating battery cycling, this lithium alloy layer was easily broken due to their volume change accompanied by lithiation/delithation. (Phase transition) As a result, the same deterioration process as that of the conventional lithium cathode is shown. In this study, the new concept of artificial alloy protection layer (APL) was designed using lithium-aluminum alloy (Li-Al). This new APL disconnected the electronic network between Li-Al and Lithium electrode to prevent the phase transition of lithium alloys. The APL was successfully fabricated and applied to the lithium metal anodes, resulting in decrease of overpotential and increase of 4.5 times exchange current density than reference electrode. This research offers new concept of designing protection layer for planar lithium dendrite growth with high stability.