Multifunctional MoSe_2@rGO coating on the cathode versus the separator as an efficient polysulfide barrier for high-performance lithium-sulfur battery

摘要

The practical applications of high-performance lithium-sulfur batteries are severely hindered by the insulating nature of sulfur and intractable shuttling of the polysulfide intermediates. In this work, we report a novel MoSe2@rGO cathode coating consisting of two-dimensional MoSe2 and reduced graphene oxide (rGO) as a multifunctional barrier to suppress polysulfide shuttling. Few-layered MoSe2 nanosheets are in situ grown on the rGO surface by basal plane contact. Besides, some cotton-like MoSe2 nanospheres assembled from porous nanosheets are decorated on the surface of rGO nanosheets. Benefitted from the strong chemical adsorption of polar MoSe2 and excellent electrical conductivity of rGO, the MoSe2@rGO coatings exhibit highly efficient polysulfide anchoring and significantly enhanced electrocatalytic chemistry. Moreover, the MoSe2@rGO cathode coatings are much superior to its separator coatings in the recycling of the adsorbed active materials because of good interfacial conductivities. The cell with the MoSe2@rGO cathode coating delivers a high reversible capacity up to 1216 mAh g(-1) at 0.2 C and outstanding cycling stability with a low capacity fading rate of 0.03% at 1 C over 1000 cycles.