Probing Titanium Disulfide-Sulfur Composite Materials for Li-S Batteries via In Situ X-ray Diffraction (XRD)

Development of Li-S batteries is hindered by sluggish kinetics resulting from the intrinsic poor conductivity of sulfur and capacity degradation due to solubility of intermediate lithium polysulfides (LiPS). One strategy for overcoming these issues is to use TiS2, which is a good electrical conductor and LiPS absorbant, as an additive to sulfur electrodes. From a structural perspective, we probed TiS2-S composite materials during electrochemical discharge and charge reactions in propylene-oxide based glyme (DPGDME) electrolyte using in-situ XRD, revealing the synergistic effects of TiS2 and S in the composites. TiS2 was found to function effectively as a conductive additive and improve the utilization of sulfur. Intercalation of Li+ into TiS2 takes place simultaneously with the sulfur-lithium reaction, and contributes favorably to the total realized capacity. (C) 2017 The Electrochemical Society. All rights reserved.