Hollow carbon dual-decorated with MnO2 shielding layer and carbon nanotube as a sulfur host for Li-S batteries

Abstract

The shuttle effect of polysulfides and sluggish reaction kinetics have been the main obstacles for the practical applications of lithium-sulfur (Li-S) batteries. Herein, we report a rationally designed sulfur cathode (DLHC/S@MnO2-ACNT) based on double-layered hollow carbon sphere (DLHC) decorated with manganese dioxide (MnO2) shielding layer and carbon nanotube conductive network (ACNT). The Ultramicrotome technique demonstrates that S and MnO2 nanosheets are mainly located into the interlayer of the DLHC. In the elaborate nanostructured protocol, the interlayer MnO2 nanosheets catalyze the conversion of polysulfides and the surface MnO2 nanosheets effectively adsorb polysulfides to suppress the shuttle effect. Additionally, the ACNT conductive network facilitates electrons/ions transport. Benefiting from the hierarchical confinement, Li-S batteries with DLHC/S@MnO2-ACNT composite cathodes exhibit a high reversible capacity of 1051 mAh g−1 at 0.5 C and a remarkable cycling stability over 500 cycles at 1 C. Even at a high sulfur loading of 4 mg cm−2, the cell delivers a superior areal capacity of 4.47 mAh cm−2. This work provides a new route to the design of hierarchical confinement sulfur hosts for high-performance Li-S batteries.