Improvement of Li-S battery electrochemical performance with 2D TiS2 additive

As a multifunctional cathode additive, TiS₂ has been used in Li-S batteries to promote sulfur utilization and improve cell cycle life. The improvement of Li-S cell electrochemical performance in the presence of TiS₂ has been attributed to the ability of TiS₂ in adsorbing polysulfide. To maximize the interaction between polysulfides and TiS₂, the 2-dimensional (2D) TiS₂ nano-sheets with highly exposed TiS₂ surface area has been successfully synthesized by a two-step sonication synthetic procedure. The 2D TiS₂ particles are micron size in the basal plane direction and are nano-sized along the c-axis direction. 2D TiS₂ nano-sheets may adsorb polysulfides more effectively than the raw TiS₂ powder. Li-S cells with 2D TiS₂ nano-sheets additive exhibit better discharge rate capability and significantly reduced capacity-fading after a long term cell cycling. This improvement can be partially attributed to the uniform distribution of 2D TiS₂ nano-sheets particles within the sulfur cathode matrix, which induces more uniform sulfur and lithium sulfide deposition during the cell charge and discharge.