Multicore closely packed ultrathin-MnO2@N-doped carbon-gear yolk-shell micro-nanostructures as highly efficient sulfur hosts for Li-S batteries

Suppressing the polysulfide shuttle effect and promoting the conductivity of electrode materials have become efficient ways to achieve high cycling stability for Li-S batteries. However, this still remains a challenge. New multicore closely packed ultrathin-MnO2@N-doped carbon-gear yolk-shell micro-nanostructures are explored as the S host material to trap polysulfides and enhance conductivity. Such composites can accommodate S mass-loading up to 80 wt% via a valid sulfur solution infiltration approach. The cooperation of ultrathin-MnO2 yolks with N-doped carbon internal gear shells can well suppress the polysulfide shuttle effect by strong chemical interactions and physical confinement as well as enhanced conductivity for excellent Li-S battery properties, which enable an initial gravimetric capacity of 1245 mA h g(-1) and a low decay rate of 0.03% per cycle over 1000 cycles at 1C. In particular, the composite delivers an initial gravimetric capacity of 1097.8 mA h g(-1) and volumetric capacity of 1059.6 mA h cm(-3) at 2C rate. Specifically, the electrochemical performance of the designed composite at different electrolyte/S ratios is firstly investigated in this study, and is a promising approach with the high-performance cathode material for Li-S batteries.

Automated summary

The new multicore closely packed ultrathin-MnO2@N-doped carbon-gear yolk-shell micro-nanostructures, explored as the S host material, show great potential in trapping polysulfides and enhancing conductivity, making them a promising high-performance cathode material for Li-S batteries.