Effect of heteroatom in conductive polymer coating of cathode materials on electrochemical performance of lithium sulfur batteries

Coating conductive polymers on carbon/sulfur (C/S) cathode is an effective strategy for improving electrochemical performances of lithium-sulfur (Li–S) batteries. Furthermore, the heteroatoms in conductive polymer coating exhibit positive effects on electrochemical property. Herein, the C/S cathode was coated by polypyrrole (PPy) and polythiophene (PTh) which were fabricated and systematically investigated to reveal the effect of nitrogen (N) and S heteroatoms on the electrochemical property. As expected, both experimental identification and theoretical calculation verified that the PPy containing N heteroatom-coated C/S cathode possessed strong chemical adsorption capability for soluble polysulfides, which suppressed shuttle effect more effectively and displayed a more stable cycling life, while the PTh@C/S cathode containing S atom presented less Li + diffusion energy barrier, which exhibited reduced polarization and superior rate performance. This work demonstrated the specific functions of N and S heteroatoms in conductive polymer coating on C/S cathode materials, indicating their promising application for advanced Li–S batteries.