Vapor phase sulfurization synthesis of interlayer-expanded MoS2@C hollow nanospheres as a robust anode material for lithium-ion batteries

Abstract

MoS2@C hollow nanospheres are synthesized by in situ vapor phase sulfurization of the spherical polypyrrole-polyoxometalate (PPy-PMo12) precursors, in which MoS2 layers with widened interlayer spacing of 0.98 nm and amorphous carbon are generated. The vapor phase sulfurization process can retain the spherical morphology of the PPy-PMo12 precursor, and facilitate the formation of the MoS2@C hollow structures. When used as anode materials for lithium-ion batteries, the MoS2@C hollow nanospheres exhibit excellent lithium storage performances compared to the bulk MoS2, including high specific capacity (1225.6 mAh g−1 at 0.1 A g−1), excellent rate capability (452 mAh g−1 at 8 A g−1 and 389.6 mAh g−1 at 10 A g−1), and good cycling stability (94.3% capacity retention after 500 cycles at 1 A g−1). The hollow structures of interlayer-expanded MoS2@C hollow nanospheres could provide more active sites and buffer the volume changes for the electrochemical reactions. Moreover, the interoverlapped architectures between MoS2 layers and carbon can greatly improve the electronic conductivity and cycle stability, thus leading to enhanced lithium storage performances.