Polysulfides Shuttling Remedies by Interface-Catalytic Effect of Mn3O4-MnPx Heterostructure
Kai Guo, Gan Qu, Jin Li, Huicong Xia, Wenfu Yan, Jianwei Fu, Pengfei Yuan, Jianan Zhang
Lithium-sulfur batteries (Li-S batteries) have attracted considerable attentions for the low cost and high theoretical energy density of sulfur. However, the Li-S batteries often undergo rapid degradation due to the severe “shuttle effect”, sluggish redox kinetics and the insulator nature of sulfur. Herein, the Mn3O4-MnPx heterostructure was constructed via the in-situ crystallization of Mn3O4-MnPx on amorphous phosphrus (P) NPs-modified carbon nanosheets. According to the experimental test and density functional theory calculation, Mn3O4 exhibits strong adsorption ability towards polysulfides. Meanwhile, MnPx dramatically catalyzes the conversion reactions between sulfur and polysulfides. The synergistic effect of Mn3O4 and MnPx facilitates the facile redox kinetics and effective entrapment of polysulfides. As a result, the improved specific capacities of 1410 and 804 mA h g-1 are obtained at 0.1 and 2 C, respectively. The capacity decay is only 0.041% per cycle over 1000 cycles at 0.5 C. This work indicuates that the interface regulation and design play an important role in advancing the electrochemical performance in Li-S batteries.