A novel wheel-confined composite as cathode in Li-S batteries with high capacity retention

Abstract

High energy density Li-S battery has attracted broad attention; however the capacity retention is still non-ideal. The major challenge is to find a way to effectively prevent the shuttle effect of the lithium polysulfides during charging/discharging. Here, we present a novel wheel-confined composite consisting of MnO2 nano-rod as wedge and SnO2 sphere as the skeleton filled with sulfur, which was synthesized using a facile chemical method. The battery with the S@MnO2@SnO2 composite as cathode exhibits a capacity as high as 1323 mAh g−1 at 0.1 C and a high capacity retention of only 0.03% decay per cycle over 500 cycles, which indicates a greatly reduced shuttle effect in Li-S batteries. The battery also shows good rate-performance and low-temperature properties. In addition, the I-V measurements and the first-principle calculations have demonstrated an enhanced electron transfer through the composite.