Abstract
Lithium-Sulfur (Li-S) batteries are regarded as one of the most promising candidates for next-generation energy storage systems due to its high theoretical energy density (2567 Wh kg-1 ), low cost, and eco-friendliness. However, the poor cycling stability and rapid capacity decay, originating from poor electronic conductivities, extreme volume changes, and shuttling effect limits the practical application of Li-S batteries. To address this limitation, researchers have attempted to introduce an interlayer between the cathode and the separator. MXenes -- a family of 2D transition metal carbides/nitrides possess several attractive properties as an interlayer in Li-S battery. This is due to its 2D structure, high mechanical strength, hydrophilic features, and highly active polar sites, which are beneficial for use in Li-S batteries. However, MXene layers can easily restack or aggregate, resulting in the hindrance of ionic transportation, hence reducing the electrochemical performance. Therefore, in this work, we attempted to grow CoSe2 nanoparticle catalysts, on the surface of MXene nanosheets to mitigate the issue of MXene restacking and also improve Li-S battery performance. The proposed separator retained a discharge capacity of 667 mAh/g after 500 cycles at 0.5 C with a capacity decay of only 0.057% per cycle, which is a significant improvement in comparison to Li-S batteries without this interlayer