Polysulfides Shuttling Remedies by Interface-Catalytic Effect of Mn₃O₄-MnP_x 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-MnP_x heterostructure was constructed via the in-situ crystallization of Mn₃O₄-MnP_x 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, MnP_x dramatically catalyzes the conversion reactions between sulfur and polysulfides. The synergistic effect of Mn₃O₄ and MnP_x 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.