Titanium(III) Sulfide Nanoparticles Coated with Multicomponent Oxide (Ti–S–O) as a Conductive Polysulfide Scavenger for Lithium–Sulfur Batteries

Abstract

In spite of the high specific capacity and energy density of Li–S batteries based on low-cost sulfur as the active material, their practical use has not yet been realized due to the undesirable formation of soluble polysulfides (PS) during electrochemical cycles and their shuttling effect. In order to minimize this serious issue caused by the active material dissolution, transition metal compounds such as oxides, nitrides, and sulfides have alternatively been used to capture the PS and also to provide electron pathways in the S electrode. However, high-performance additive materials having both high affinity to PS and high electronic conductivity have not been developed thus far. Herein, we report the preparation and application of a new additive material—titanium(III) sulfide (Ti2S3) nanoparticles covered with multicomponent (Ti–S–O) oxide (MO–Ti2S3), which can be synthesized on a large scale using an inductively-coupled thermal plasma synthesis method followed by a simple surface oxidation treatment. MO–Ti2S3 shows much higher PS affinity than other titanium compounds and electronic conductivity that is comparable to that of carbon black. Furthermore, MO–Ti2S3 shows much higher resistance to heat and oxidation while having charge–discharge stability when compared with TiS2. Finally, we show that the cyclability and specific capacity of the Li–S battery can be significantly enhanced by incorporating MO–Ti2S3 in the cathode when compared to utilizing C species.Graphical Abstract