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Compared to the monometal carbide Ni 3 C, the bimetal carbide Ni 3 ZnC 0.7 possesses the advantageous properties of both sulfophilic sites of Ni and lithophilic sites of Zn, which demonstrates efficient adsorption and catalytic effect towards LiPSs. Therefore, the Li-S battery with the Ni 3 ZnC 0.7 /Ni/NCNTs-based coating separator shows excellent performance even at the high rate of 7C. • The Ni 3 ZnC 0.7 demonstrated efficient adsorption and catalytic effect towards LiPSs. • The Ni 3 ZnC 0.7 possesses both sulfophilic sites of Ni and lithophilic sites of Zn. • The sulfophilic and lithophilic sites can enhance the catalysis of LPSs. • The Li-S battery with bimetal carbide coating shows excellent performance at 7C. The notorious shuttle effect and slow reaction kinetics of lithium polysulfides (LiPSs) severely limit the cycle stability and rate performance of lithium sulfur (Li-S) batteries. Herein, we demonstrated that the issue of shuttling effect of LiPSs could be effectively addressed by using a separator coating based on Ni 3 ZnC 0.7 bimetal carbide nanoparticles dispersed in nitrogen-doped porous carbon material matrix containing small amount of Ni metal particles, namely Ni 3 ZnC 0.7 /Ni/NCNTs. When used as a separator coating of Li-S cells, the Ni 3 ZnC 0.7 bimetal carbides demonstrated efficient adsorption and catalytic effect towards LiPSs, inhibiting the shuttle effect and enhancing the electrochemical performance of device. The Li-S cell still maintained excellent charging and discharging platform even at a high rate of 7C. Theoretical calculation shows that, compared to the monometal carbide Ni 3 C, the bimetal carbide Ni 3 ZnC 0.7 possesses the advantageous properties of both sulfophilic sites of Ni and lithophilic sites of Zn, resulting in reduced energy barriers for lithium ion diffusion and improved catalytic capability, thus enhancing reaction kinetics of LiPSs. This work paves a new way to resolving the critical issues of shuttle effect, cycle stability and rate capability of Li-S batteries by taking advantage of synergistic effect of Ni and Zn in the bimetal carbide. [ABSTRACT FROM AUTHOR]

The lithium–sulfur battery is considered as one of the most promising next-generation energy storage systems owing to its high theoretical capacity and energy density. However, the shuttle effect in lithium–sulfur battery leads to the problems of low sulfur utilization, poor cyclability, and rate capability, which has attracted the attention of a large number of researchers in the recent years. Among them, the catalysts with efficient catalytic function for lithium polysulfides (LPSs) can effectively inhibit the shuttle effect. This review outlines the progress of catalyst materials for lithium–sulfur battery in recent years. Based on the structure and properties of the reported catalysts, the development of the reported catalyst materials for LPSs was divided into three generations. We can find that the design of highly efficient catalytic materials needs to consider not only strong chemical adsorption on polysulfides, but also good conductivity, catalysis, and mass transfer. Finally, the perspectives and outlook of reasonable design of catalyst materials for high performance lithium–sulfur battery are put forward. Catalytic materials with high conductivity and both lipophilic and thiophile sites will become the next-generation catalytic materials, such as heterosingle atom catalysis and heterometal carbide. The development of these catalytic materials will help catalyze LPSs more efficiently and improve the reaction kinetics, thus providing guarantee for lithium sulfur batteries with high load or rapid charge and discharge, which will promote the practical application of lithium–sulfur battery. [ABSTRACT FROM AUTHOR]

• The 3D Co/NCNS/CNT nanocomposite is prepared by the carbonization of MOF. • The Co/NCNS/CNT can effectively adsorb and catalyze the lithium polysulfides. • Co/NCNS/CNT serves as the separator coating in Li-S battery with high performance. Lithium sulfur (Li-S) battery is regarded as one of the most promising next generation high-energy storage systems. However, the shuttle effect and sluggish redox kinetics of lithium polysulfides always compromise the cycling performance of Li-S batteries. Herein, an effective strategy is presented to fabricate high-performance Li–S batteries using a 3D network-like nanocomposite of Co/NCNS/CNT, which is obtained via the well-distributed composition of the carbon nanotubes (CNTs) (in situ formed and added) with nitrogen-doped carbon nanosheets (NCNS) as well as Co nanoparticles from carbonization of the nitrogen-rich bio-MOF-100 nanosheets at an inert atmosphere. Owing to good sulphiphilicity, excellent conductivity and high catalytic activity from Co-N x and Co nanoparticles, Co/NCNS/CNT nanocomposite could effectively adsorb and catalyze the fast conversion of lithium polysulfides. When serving as the separator coating for Li-S cells, the cell shows excellent performances with an initial capacity of 972.4 mAh/g at 2C under a sulfur loading of 2.0 mg/cm2, and excellent cycling stability with the capacity decay of 0.05% per cycle during the 1000 long-term cycles. Furthermore, even at a high sulfur loading of 5 mg/cm2, the specific capacity of 522.1 mAh/g (2.61 mAh/cm2) can be maintained after 500 cycles at 1 C, thus providing a promising path toward advanced Li–S batteries. [ABSTRACT FROM AUTHOR]