The polyethylene glycol@MoO3/canbon nanotubes/S composite fixing polysulfides for lithium-sulfur batteries

Lithium-sulfur batteries are the extremely promising next generation lithium-ion batteries, but solving the shuttle effect of polysulfide is challenging. Here, the polyethylene glycol@MoO 3 /carbon nanotubes/S composite（PEG@MoO 3 /CNTs/S）is prepared in this paper. PEG can trap polysulfides and suppress the shuttle effect. Meanwhile, the polar MoO 3 can effectively limit the transfer of polysulfides by chemisorption. Furthermore, the CNTs with the excellent electrical conductivity and mechanical properties is used as the substrate in lithium-sulfur batteries. The 2.5-PEG@MoO 3 /CNTs/S (2.5 refers to percentage of PEG coated) cathode exhibits a high initial discharge capacity (1327.4 ​mAh g −1 at 0.1C), an outstanding cycling stability (capacity fading rate of 0.067% per cycle at 0.5C over 800 cycles) and an excellent rate performance (899.1 ​mAh g −1 at 1C). The 2.5-PEG@MoO 3 /CNTs/S cathode exhibits an outstanding cycling stability and an excellent rate performance. The discharge capacity of the 2.5-PEG@MoO 3 /CNTs/S cathode is 992.9 ​mAh g −1 at 0.5C. After 800 cycles, the capacity decreases to 462.5 ​mAh g −1 with an ultralow capacity decay of 0.067% per cycle. The 2.5-PEG@MoO 3 /CNTs composite has stronger adsorption capacity for polysulfide. The obtained MoO 3 /CNTs/S coated with PEG provides a new and efficient strategy for absorbing polysulfide, improving the cycling stability and delivering high coulombic efficiency. • The PEG@MoO 3 /CNTs/S composite is prepared. • The PEG layer restricts the polysulfide to the cathode and provides a buffer space to alleviate the volume expansion. • The polar MoO 3 can inhibits shuttle effect by in-situ adsorption of polysulfides. • The synergistic effects of MoO 3 , conductive CNTs and PEG materials.