The preparation of cementite nanosheets and their application as cathodes for advanced energy storage

Novel cementite Fe3C nanosheets for sulfur host are prepared by facile heating method. After that, the Fe3C nanosheets/sulfur (FCNSs/S) composites as cathode materials for lithium-sulfur batteries are also synthesized via heating method. The as-prepared FCNSs materials have many advantages, including high electronic conductivity, abundant mesoporous structure, and high specific surface area. Besides, the FCNSs could form chemical affinity for the soluble polysulfide. Due to these above advantages, the poor electronic conductivity and polysulfide migration in lithium-sulfur batteries could be improved and inhibited. As a result, the as-prepared FCNSs/S composite cathodes deliver high initial specific discharge capacity of 1396 mAh/g at 0.1 C rate and an excellent long cycle stability at 2 C rate. These outstanding electrochemical performances make the FCNSs/S composites as an excellent candidate for lithium-sulfur batteries.