Experimental and first-principles study on amorphous aluminum nitride induced island-like nucleation and planar growth of lithium metal anode

Abstract

Dendritic Li growth is the root hurdle against the implementation of lithium metal anode because it brings safety hazard, low columbic efficiency and inferior cycle life. Customized strategies have been investigated to achieve uniform lithium deposition. However, little attention has been paid to the fundamental understandings of intrinsic electrocrystallization, especially the nucleation behavior, of lithium deposition. In this work, the deposition behavior of Li metal on amorphous substrate and the difference of Li electrocrystallization among various crystallinities have been studied by both experiments and first-principles calculations. A 2D island-like Li nucleation rather than dispersed submicro grains is achieved on amorphous-AlN modified Cu current collector. The mechanism underlying the amorphism-induced nucleation of Li metal includes the enhanced absorption capacity of the initially deposited Li layer (at least four layers) to subsequent Li layers endowed by amorphous AlN and the preference to Li extending rather than dendritic growth on amorphous AlN. With this amorphism-induced 2D island-like nucleation, Li deposition on amorphous AlN exhibits a smooth and planar morphology, accompanied by the uniformity in thickness. Therefore, both half-cells and full-cells present enhanced cycling stability and higher CE using amorphous-AlN modified Cu current collector.