Enhanced multiple anchoring and catalytic conversion of polysulfides by SnO2-decorated MoS2 hollow microspheres for high-performance lithium-sulfur batteries

Abstract Lithium-Sulfur (Li-S) batteries are very competitive in energy storage equipment due to their high theoretical capacity and low cost of raw materials. However, the serious polysulfide "shuttle effect", volume expansion effect and slow conversion reaction kinetics of Li−S batteries during the charge/discharge cycle process still need to be resolved urgently. Herein, we prepared a novel sulfur host of SnO2-decorated MoS2 hollow microspheres (SnO2-MoS2 HMSs). The unique hollow structure provides enough space to accommodate a large amount of sulfur and effectively adapts to its large volume expansion during charge and discharge process. On the other hand, the SnO2 nanoparticles that attached to the surface of the MoS2 nanosheets will accelerate the catalysis of MoS2 and enhance the bonding strength with the polysulfide intermediates through the S−Sn−O chemical bond, which further inhibits the shuttle effect. The newly synthesized SnO2-MoS2 HMSs cathode has achieved excellent electrochemical performance. The initial discharge specific capacity of 1326.4 mAh g−1 was obtained at 0.2 C, and after 100 cycles, the specific capacity of the SnO2-MoS2 HMSs/S cathode only decreased slightly to 1183.8 mAh g−1, its capacity retention rate reaching as high as 89.2%. We expect the newly synthesized hollow structured MoS2 with SnO2 decoration provides a new strategy for the construction of Li-S battery cathode materials.