Nitrogen-Doped Mesoporous Carbon: A Top-Down Strategy to Promote Sulfur Immobilization for Lithium-Sulfur Batteries

Abstract

The loss of active sulfur material is a challenge in the application of lithium-sulfur (Li-S) batteries. To immobilize sulfur, a nitrogen-doped mesoporous carbon (PMC) was synthesized with polyaniline (PANi) as the carbon source, which was used for development of Li-S batteries. The nitrogen content and pore system of the PMCs were modulated by varying the pyrolysis temperature to impart good electrochemical properties to the Li-S cells. As a result, the optimal capacity reversibility was obtained with the PMC synthesized at 700 degrees C that consisted of 12.8% nitrogen. The enhanced cycle performance of Li-S cells was also validated at high sulfur contents up to 70% and high C-rates up to 2C. Furthermore, such sulfur/PMC cathodes could alleviate volume expansion during the discharge process. The results suggest that our synthesized nitrogen-doped PMCs prepared by this top-down strategy are promising materials to immobilize active sulfur in Li-S batteries.