Hollow α-MnS Spheres and Their Hybrids with Reduced Graphene Oxide: Synthesis, Microwave Absorption, and Lithium Storage Properties.

Novel α-MnS hollow spheres (MHSs) have been fabricated successfully by a one-pot template-free solvothermal method. The as-synthesized α-MnS spheres have diameters of about 3-5 μm and porous shells of thickness about 0.5 μm composed of numerous nanocrystals. The samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption. Time-dependent morphology evolution suggested that transformation of chemical components and Ostwald ripening play vital roles for these hollow structures with a porous shell. The possible formation mechanism for the fabrication of MHSs is proposed. Meanwhile, MHS-reduced graphene oxide (RGO) hybrids have been prepared in the presence of graphene oxide (GO) by using the same procedure. The amount of GO can affect the morphology of α-MnS crystals in hybrids. The microwave absorption and lithium storage properties of the pure MHSs and MHS-RGO hybrids were studied in detail. Compared with pristine MHSs, the MHS-RGO hybrids possess remarkably enhanced microwave absorption and lithium storage properties. The enhanced microwave absorbing and electrochemical properties are also explained.