Cobalt-based organic framework derived N-doped carbon with CoO/Co3O4 nanoparticles as polysulfide anchor for high-performance of lithium–sulfur batteries

Abstract

Lithium-sulfur (Li–S) batteries became recently one of the candidates for the next generation of energy storage devices. However, the rapid capacity decay caused by the “shuttle effect” of polysulfides hinders its large-scale applications. In this study, we synthesized CoO/Co3O4 nanoparticles embedded in N-doped carbon (CoO/Co3O4/NC) via two-step heat treatments of cobalt-based organic framework (ZIF-67 cube). The CoO/Co3O4/NC were prepared by tuning the surface components of pristine MOF-derived carbon skeletons with a controllable temperature and atmosphere. S/CoO/Co3O4/NC electrode delivered a high discharge capacity of 1211.6 mAh g−1 at 0.2C, and low capacity attenuation of 0.04% per cycle over 1000 cycles at 1 C. The good electrochemical performance can be attributed to the CoO/Co3O4/NC hosts that are featured with strong polar chemisorption of polysulfides by CoO/Co3O4, high electronic conductivity of ZIF-67 cubes derived carbon, the stable structure of hollow carbon. This work shows that S/CoO/Co3O4/NC can be a potential candidate for cathode material applied in Li–S batteries.