Journal of Power Sources, Vol.270, 101-105, 2014
Sulfur/lithium-insertion compound composite cathodes for Li-S batteries
A part of carbon additives in sulfur cathodes is replaced by lithium-insertion compounds as they can contribute extra capacity and increase the overall energy density. Accordingly, VO2(B) and TiS2 were incorporated into sulfur cathodes as they can work within the same voltage window as that of sulfur. However, VO2(B) was found to be incompatible with the glyme-based electrolytes that are usually used in Li-S cells, but TiS2 performs well while coupled with sulfur. The S/C/TiS2 composite cathode delivers 252 mAh g(-1) more than that of pristine sulfur cathode (1334 mAh g(-1) vs. 1082 mAh g(-1)). The increased capacity is not only due to the contribution by TiS2 itself but also due to a better active-material dispersion and utilization. Serving as active reaction sites during cycling, TiS2 suppresses agglomeration of sulfur and facilitates better ionic! electronic transport within the cathode structure. This composite cathode design provides another direction for Li-S batteries to improve the overall energy density. (C) 2014 Elsevier B.V. All rights reserved.
Keywords:Lithium-sulfur batteries;Cathode materials;Sulfur composite cathodes;Vanadium oxide;Titanium disulfide