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

CoS2 and FeS2 nanoparticles withmesoporousstructures embedded in carbon polyhedrons are prepared by reasonabledesign of materials (CoS2-FeS2-NC), which areused as a modified cathode material. This composite material can limitthe 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 electrodeshave the best cycle and rate performance. The S/CoS2-FeS2-NC cathode's initial discharge capacity at 0.2C is938.9 mAh g(-1), while its reversible capacity remains394.8 mAh g(-1) after 200 cycles, with a 0.28% declineon average. S/CoS2-NC and bare sulfur cathodes have maximaldischarging 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 maintainedafter 200 cycles. So, S/CoS2-FeS2-NC has excellentelectrochemical properties.