1T-MoS_2 nanotubes wrapped with N-doped graphene as highly-efficient absorbent and electrocatalyst for Li-S batteries

摘要

A novel three-dimensional porous graphene/MoS2 hybrid is synthesized through a facile spray-drying approach. This hybrid is constructed with two-dimensional N-doped graphene nanosheets wrapping one-dimensional nanotubes self-assembled by vertically oriented few-layered 1T-MoS2. Due to its well-designed nanoarchitecture, the hybrid owns several advantages: the metallic 1T-MoS2 and highly conductive graphene skeleton facilitates electron transfer; with abundant specific area and electrocatalytic active sites, the unique hollow nano architecture enables efficient electrolyte infiltration and Li-ion transfer. The experiments of lithium polysulfides adsorption and in-situ Raman spectra confirm that the hybrid acts as both excellent chemical absorbant and high-efficiency electrocatalyst for the transition of long-chain lithium polysulfides. Benefiting from these merits, the cathode delivers outstanding electrochemical properties with a superior reversible capacity of 1219 mAh g(-1) (after 200 cycles at 0.2 C), a low long-term cycling capacity decay of 0.039% per cycle (500 cycles at 1 C), and excellent rate performances.