Li2S/transition metal carbide composite as cathode material for high performance lithium-sulfur batteries

Lithium sulfide (Li2S) with high capacity (1166 mAh g(-1)) is a promising cathode material for lithium/sulfur (Li/S) batteries which can be paired with non-lithium anodes for avoiding safety issues. Nonetheless, the application of Li2S in Li/S cells is limited because their low electronic and ionic conductivities, on one hand, and the polysulfides dissolution problems, on the other hand. In this study, Li2S/Ti3C2Tx composite has been prepared by a solution-based method followed by high energy ball milling process. XRD and SEM techniques revealed the presence of nano-size Li2S particles in the prepared composite. The as-prepared electrode exhibited an initial capacity of 708 mAh g(-1) with a capacity retention of similar to 74.5% after 100 cycles (528 mAh g(-1)), which was higher than that of the microsize commercial Li2S at 0.1 C. This superior performance was attributed to the high electrical conductivity and two dimensional structure of Ti3C2Tx. These advantages result in the reduction of energy barrier for the transport of Li ions through nano-size Li2S particles. Consequently, a homogeneous distribution of Li2S particles in the composite inhibited the lithium polysulfide dissolution. The results confirmed the Li2S/Ti3C2Tx composite based electrode as a potential candidate for applying in metal-free anodes of rechargeable Li/S batteries.