Sulfur loads under high temperature on the surface of C/SnO2 to enhance first platform capacity of lithium-sulfur batteries

Abstract

Polysulfides are easily dissolved during the redox reaction process of Li-S batteries, which may be severe when current density and cycle number increase. Increasing capacity of the first platform effectively is beneficial for improving cycling stability. Physical sulfur loads are benefit for achieving high-capacity storage. However, the influence of composite electrodes with sulfur loads under high temperature on cycling stability of the first platform capacity has not been studied. Sulfur particles are loaded on the surface of C/SnO2 under high temperature in this work. C/SnO2/S and C/SnS/S composite electrodes are obtained by controlling sulfur contents. Results show that C/SnS/S composite electrodes display better cycling stability (1161 mAh⋅g−1) than C/SnO2/S composite electrodes at 1C after 100 cycles, especially in P1 platforms (724 mAh⋅g−1). When cycling number increases to 1000, C/SnS/S composite electrodes still possess good cycling stability (274.8 mAh⋅g−1) at 1C. Good cycling stability is ascribed to strong surface activities of sulfur in SnS and rapid electron transportation abilities during the cycling process. Studying sulfur-loading methods under high temperature is beneficial for obtaining high cycling performance composite electrodes for lithium-sulfur batteries.