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.

Key words: Li-S batteries, SnO₂-decorated hollow MoS₂ microspheres, S-Sn-O chemical bond, Electrochemical performance