MoC/N-C composites derived from Mo doped ZIF-8 for separator modification of lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) have been recognized as one of the most hopeful new energy storage devices. However, the shuttle effect of polysulfides seriously affects the commercial use of LSBs. In order to alleviate the shuttle effect, in this paper, A novel MoC/N-C composite was firstly prepared by calcining Mo doped ZIF-8 precursor in a nitrogen environment, and then the as prepared MoC/N-C composite was coated on the surface of the commercial polypropylene separator to act as a block layer of lithium polysulfides. The N-C derived from ZIF-8 under high-temperature carbonization can provide good electrical conductivity and block the diffusion of polysulfides by physical adsorption. At the same time, MoC will provide abundant chemisorption sites to effectively hinder the shuttle of polysulfides and promote their redox reactions. Because of the adsorption and catalytic function of MoC/N-C composite, the LSB battery show excellent electrochemical properties even at a high sulfur loading.