Unveiling the synergistic effect of polysulfide additive and MnO2 hollow spheres in evolving a stable cyclic performance in Li-S batteries.

Abstract

Herein, we demonstrate a synergistic approach involving polar-based oxide and polysulfide additives for effectively suppressing polysulfide dissolution during cycling. The MnO2 hollow spheres not only provide physical confinement for the polysulfide species but also enable strong chemical interactions between polysulfide species and oxides, while the added polysulfide furnishes a mass buffering effect and compensates for the capacity losses due to partial cathode dissolution during discharge. The capacity retentions of S/KB, S/KB/LiPS, S/KB/MnO2, and S/KB/MnO2/LiPS composite cathodes are 31%, 45%, 59%, and 91% respectively. The remarkable capacity retention of the S/KB/LiPS/MnO2 composite electrode is mainly attributed to the synergistic effect between MnO2 and polysulfide additives.