CoS2 and FeS2 Nanoparticles Embedded in Carbon Polyhedrons for Lithium–Sulfur Batteries

Abstract

CoS2 and FeS2 nanoparticles with mesoporous structures embedded in carbon polyhedrons are prepared by reasonable design of materials (CoS2-FeS2-NC), which are used as a modified cathode material. This composite material can limit the shuttling of polysulfides and catalyze and adsorb polysulfides. Further, electrochemical properties of Li–S batteries are enhanced. Li–S batteries using S/CoS2-FeS2-NC electrodes have the best cycle and rate performance. The S/CoS2-FeS2-NC cathode’s initial discharge capacity at 0.2C is 938.9 mAh g–1, while its reversible capacity remains 394.8 mAh g–1 after 200 cycles, with a 0.28% decline on average. S/CoS2-NC and bare sulfur cathodes have maximal discharging capacities of 82.3 and 63.8% of S/CoS2-FeS2-NC cathodes at 0.2C. The initial discharge capacity of S/CoS2-FeS2-NC at 0.5C is 795.6 mAh g–1, and the capacity of 354.4 mAh g–1 is maintained after 200 cycles. So, S/CoS2-FeS2-NC has excellent electrochemical properties.