Encapsulating of Sulfur and Acetylene Black with Manganese Dioxide Nanosheets for High-Performance Lithium–Sulfur Batteries

Abstract

A novel acetylene black (AB) and sulfur composite wrapped by manganese dioxide nanosheets (MnO 2 @AB/S) as a cathode material for lithium-sulfur (Li-S) batteries was prepared. The MnO 2 @AB/S composite was first prepared by simple melt-diffusion sulfur on/into AB followed by encapsulating by the two dimensional MnO 2 nanosheets. Surface modification on the sulfur and AB composite would be an efficient strategy to enhance the cycle stability and to improve the insulating nature of sulfur. The MnO 2 nanosheets also increase high active contact area to improve the conductivity and stability of the cathode. The as-prepared cathode material with a high area sulfur loading of 6.19 mgcm -2 delivers a high initial discharge capacity of 994.4 mA h g -1 and the coulombic efficiency is up to 91.4% at high current rate of 1 C compared with AB/S composite. The MnO 2 @AB/S electrode is promising as a potential practical application for lithium-sulfur batteries.