Enhancing performance of Li-S batteries by coating separator with MnO @ yeast-derived carbon spheres

Lithium-sulfur battery is a potential next generation energy storage technology due to its relatively low price, environmental benign and high theoretical energy density. However, the shuttling of soluble polysulfides between cathode and anode as the major technical problem causes rapid capacity fading of lithium-sulfur battery. Here, a multifunctional interlayer between cathode and separator was designed by introducing MnO particles in yeast-derived carbon spheres to effectively mitigate the shuttling problem and improve the utilization of sulfur. In the coated layer, the high level of graphitization of carbon spheres could be beneficial for facilitating ion transfer and expanding the contact area of polysulfide species. In the meantime, the polar MnO material was adopted to block polysulfides via strong chemical adsorption. The resultant lithium-sulfur batteries exhibit a high initial capacity of 800.2 mA h g(-1) at the current density of 1600 mA g(-1). And after 100 cycles the capacity is 642.7 mA h g(-1) with the fading rate of only 0.2% per cycle. Additionally, polysulfide species blocked by physical and chemical effect could be reutilized in the coated layer, which improves the utilization of sulfur active materials. In summary, the combination of metal oxides and biomass-derived carbon in designing the novel coated separator would provide new avenue for preparing carbon-coated material and facilitate the further development of lithium-sulfur batteries. (C) 2019 Elsevier B.V. All rights reserved.