A gradient topology host for a dendrite-free lithium metal anode

Abstract

Lithium metal is a “holy grail” anode (LMA) for next-generation rechargeable batteries. However, the uncontrollable growth of Li dendrites and infinite volume change plague their practical applications. Herein, we propose a 3D topological host as a stable LMA, which is realized by gradient decoration of carbon cloth with SiC whiskers (SiC/CC). The gradient distribution of SiC whiskers leads to a gradient electric field and induces a bottom-up lithium deposition process. The symmetric cell with a Li@SiC/CC LMA exhibits a low overpotential up to 1000 h at 2 mA cm−2 with a capacity of 3 mA h cm−2. An average Coulombic efficiency of as high as 98.3% is remained in the full cell even after 100 cycles with a capacity of 3 mA h cm−2. Experimental and calculation results demonstrate that such a knitted network increases the utilization of the host and further suppresses the dendrite growth during plating. Moreover, this topological host reduces the local size of Li deposits and alleviates their detachment to form “dead Li” during the stripping process. This novel strategy offers a straightforward approach to construct a gradient topological host for reliable LMAs with high energy densities.