Electrochemical properties of hollow-structured MnS-carbon nanocomposite powders prepared by a one-pot spray pyrolysis process.

Spherical, hollow MnS-C composite powders were prepared from a solution of manganese salt, thiourea, and sucrose by one-pot spray pyrolysis. The MnS-C composite powders were generated by direct sulfidation of MnO with hydrogen sulfide gas generated in situ by decomposition of thiourea during spray pyrolysis. Sucrose, which is used as a carbon source material, plays a key role in the formation of the MnS-C composite powders by improving the reducing atmosphere around the powders. Dot-mapping images of the composite powders demonstrated uniform distribution of the manganese, sulfur, and carbon components within the MnS-C composite powder. Fine crystals of MnS were uniformly mixed with carbon derived from polymerization and carbonization of sucrose. The carbon content of the MnS-C composite powders was 26 wt%. The discharge capacities of the MnS-C composite powders in the 2nd and 200th cycles were 863 and 967 mA h g(-1), respectively, at a current density of 1000 mA g(-1). The spherical and hollow morphology of the MnS-C composite powders was completely retained, even after 200 cycles. The enhanced cycling and rate performance of the MnS-C composite powders is ascribed to the structural stability of the composite powders.