Design of three-dimensional carbon-based hosts for a high-performance lithium metal anode

Abstract

In recent years, as the demand of eco-friendly electric vehicles (EV) dramatically increases, it is urgent to develop a lithium-ion battery which has the high-power and high-energy density. Among the anode materials, lithium metal is a potential candidate for a high-capacity anode owing to the lowest redox potential (-3.04 VSHE) and the highest theoretical specific capacity (3860 mAh g-1) compared to commercialized graphite anode. However, the nature of dendritic growth of Li metal leads to a severe thickness change and a significant decrease in Coulombic efficiency during prolonged cycles. One promising strategy to suppress dendrite is employing 3D hosts which have high specific surface area and low localized current density. Nevertheless, in case of the host with low porosity and pore size, the Li-ion preferentially deposited on the top of the surfaces rather than inside of the host. Moreover, the high weight of the metallic host such as copper and nickel should affect low gravimetric energy density of battery. In this work, we propose 3D carbon nanotube (CNT) host coated separator for a dendrite-free LMA. To enhance specific energy density, we employ a light-weight one-dimensional cross-linking carbon material, CNT and a polymer template for pore-forming agent. By increasing porosity, CNT host exhibits higher cycling capability and higher rate performance, compared to pristine CNT host. Furthermore, the effect of 3D CNT hosts on the electrochemical deposition/stripping behaviors of Li metal will be discussed by SEM images and in-situ optical microscopy.