2D spinel ZnCo2O4 microsheet-coated functional separator for promoted redox kinetics and inhibited polysulfide dissolution

• 作者: Jeong Seok Yeon Tae Ho Park Young Hun Ko Periyasamy Sivakumar Jun Su Kim Youngkywon Kim Ho Seok Park
• 来源期刊: 能源化学
• 年，卷（期）: 2021,（4）
• 页码范围: 468-475
• 页数: 8页
• 语种: 英文

摘要

Lithium-sulfur(Li-S)batteries are receiving increasing attention as one of the potential next-generation batteries,owing to their high energy densities and low cost.However,practical Li-S batteries with high energy densities are extremely hindered by the sulfur loss,low Coulombic efficiency,and short cycling life originating from the polysulfide(LiPS)shuttle.In this study,two-dimensional(2D)ZnCo2O4 micro-sheets fabricated by a facile hydrothermal process are employed to modify the separator,for improving the electrochemical performances of Li-S cells.The resulting 2D ZnCo2O4-coated separator features a coating thickness of approximately 10 μm,high ionic conductivity of 1.8 mS/cm,and low mass loading of 0.2 mg/cm2.This 2D ZnCo2O4-coated separator effectively inhibits LiPS shuttle by a strong chemical interaction with LiPS as well as promotes the redox kinetics by ZnCO2O4-coated layers,as determined by X-ray photoelectron spectroscopy analysis,self-discharge,time-dependent permeation test,Li sym-metric cell test,and Li2S nucleation analyses.Consequently,the Li-S batteries based on the 2D ZnCo2O4-coated separator exhibit a high initial discharge capacity of 1292.2 mAh/g at 0.1 C.Moreover,they exhibit excellent long cycle stability at 1 and 2 C with capacity retention of 84％and 86％even after 800 cycles,corresponding to a capacity fading rate of 0.020％and 0.016％per cycle,respectively.Effectively,these Li-S cells with a high sulfur loading at 5.3 mg/cm2 and low electrolyte concentration of 9 uL/mg deliver a high discharge capacity of 4.99 mAh/cm2 after 200 cycles at 0.1 C.