Graphene-Enabled Electric-Field Regulation and Ionic Redistribution Around Lithiophilic Aurum Nanoparticles Toward a Dendrite-Free and 2000-Cycle-Life Lithium Metal Battery.

Abstract

Lithium metal batteries (LMBs) have attracted extensive attention owing to their high energy density. However, the uncontrolled volume changes and serious dendrite growth of the Li metal anode have hindered their commercialization. Herein, a three-dimensional Cu foam decorated with Au nanoparticles and conformal graphene layer was designed to tune the Li plating/stripping behaviors. The 3D-Cu conductive host anchored by lithiophilic Au nanoparticles can effectively alleviate the volume expansion caused by the continuous plating/stripping of Li and reduce the nucleation energy barrier. Notably, the conductive graphene not only facilitates the transfer of electrons, but also acts as an ionic rectifier, thereby avoiding the aggregation of local current density and Li+ ions around Au nanoparticles and enabling the uniform Li+ flux. As a result, the G-Au@3D-Cu/Li anode ensures the non-dendritic and homogeneous Li+ plating/stripping. Electrochemical results show that the symmetric G-Au@3D-Cu/Li cell delivers a low voltage hysteresis of 110 mV after 1000 h at 1 mA cm-2 . Matched with a layered LiNi0.6 Co0.2 Mn0.2 O2 cathode, the NCM622||G-Au@3D-Cu/Li full cell exhibits a long cycle life of 2000 cycles and an ultra-low capacity decay rate (0.01 % per cycle).