Li-S Cathodes with Extended Cycle Life by Sulfur Encapsulation in Disordered Micro-Porous Carbon Powders

Sulfur cathodes have excellent theoretical properties for use as positive electrodes in rechargeable lithium batteries, but lack long-term stability required of practical secondary battery systems. To deal with this issue, high capacity Lithium-Sulfur cathodes were prepared through sulfur impregnation of disordered micro-porous carbon powders that have high surface-area. By using microporous carbon as a matrix for sulfur cathodes and lithium nitrate as an additive to the electrolyte solution, that suppresses the shuttle phenomena in Li-sulfur batteries, we managed to achieve a reversible capacity of over 500 mAh/g for 1000 cycles with a Columbic efficiency approaching 100% throughout cycling. The influence of the volume of the electrolyte solutions in Li-S cells was further evaluated by analyzing their voltage profiles during cycling. (C) 2014 The Electrochemical Society. All rights reserved.