A 3D Hierarchical Host with Gradient‐Distributed Dielectric Properties toward Dendrite‐free Lithium Metal Anode

Abstract

The conventional conductive three‐dimensional (3D) host fails to effectively stabilize lithium metal anodes (LMAs) due to the internal incongruity arising from nonuniform lithium‐ion gradient and uniform electric fields. This results in undesirable Li "top‐growth" behavior and dendritic Li growth, significantly impeding the practical application of LMAs. Herein, we construct a 3D hierarchical host with gradient‐distributed dielectric properties (GDD‐CH) that effectively regulate Li‐ion diffusion and deposition behavior. It comprises a 3D carbon fiber host modified by layer‐by‐layer bottom‐up attenuating Sb particles, which could promote Li‐ion homogeneously distribution and reduce ion concentration gradient via unique gradient dielectric polarization. Sb transforms into superionic conductive Li3Sb alloy during cycling, facilitating Li‐ion dredging and pumps towards the bottom, dominating a bottom‐up deposition regime confirmed by COMSOL Multiphysics simulations and physicochemical characterizations. Consequently, a stable cycling performance of symmetrical cells over 2000 h under a high current density of 10 mA cm−2 is achieved. The GDD‐CH‐based lithium metal battery shows remarkable cycling stability and ultra‐high energy density of 378 Wh kg‐1 with a low N/P ratio (1.51). This strategy of dielectric gradient design broadens the perspective for regulating the Li deposition mechanism and paves the way for developing high‐energy‐density lithium metal anodes with long durability.