3D core–shell MoS2 superspheres composed of oriented nanosheets with quasi molecular superlattices: mimicked embryo formation and Li-storage properties

Abstract

Monodispersed 3D core–shell superspheres consisting of oriented MoS₂ nanosheets have been successfully synthesized on the large scale with a one-pot approach combining soft- and self-templated methods. Specifically, MoO_x (x = 2–3) nanoclusters and MoS₂ layers first self-assemble together with (CTAB)₂S_y (y = 1 or 2) to form solid hybrids, MoO_x–MoS₂@(CTAB)₂S_y spheres at 160 °C, and most of the MoO_x nanoclusters then convert to MoO₂ and 2H-MoS₂ at 180 and 200 °C, respectively. 3D core–shell superspheres can be finally constructed with 2H/1T-MoS₂ nanosheets with abundant O-dopants and defects at 220 °C. The expanded d-spacings of the (002) crystal plane reveal the formation of quasi molecular superlattices for partially intercalating (CTAB)₂S molecules into 2D MoS₂ nanosheets. The dynamic composition and nano/microstructural evolution of the materials in a one-pot reaction demonstrates a mimicked embryo formation based on in situ anion-exchange. The 3D core–shell superspheres can be applied to assemble anodes for lithium ion batteries (LIBs) with excellent performance, after being coated with reduced graphene oxide (RGO).