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Lithium-sulfur batteries (LSB) show excellent potential as future energy storage devices with high energy density, but their slow redox kinetics and the shuttle effect seriously hinder their commercial application. Herein, a 0D@2D composite was obtained by anchoring polar nano-TiO 2 onto a 2D layered g-C 3 N 4 surface in situ, and a functional separator was prepared using multi-walled carbon nanotubes as a conductive substrate. Due to their long-range conductivity, multi-walled carbon nanotubes make up for the low conductivity of TiO 2 @g-C 3 N 4 to some extent. A lithium-sulfur battery prepared with a modified separator exhibited excellent long-term cycle performance, a good lithium ion diffusion rate, and rapid redox kinetics. The initial specific discharge capacity of the composite was 1316 mAh g -1 at 1 C, and a high specific discharge capacity of 569.9 mAh g -1 was maintained after 800 cycles (the capacity decay rate per cycle was only 0.07%). Even at the high current density of 5 C, a specific capacity of 784 mAh g -1 was achieved. After 60 cycles at 0.5 C, the modified separator retained the discharge capacity of 718 mAh g -1 under a sulfur load of 2.58 mg cm -2 . In summary, the construction of a heterojunction significantly improved the overall cycle stability of the battery and the utilization rate of active substances. Therefore, this study provides a simple and effective strategy for further improving the overall performance and commercial application of lithium-sulfur batteries.

Lithium-sulfur batteries exhibit great potential as one of the most promising energy storage devices due to their high theoretical energy density and specific capacity. However, the shuttle effect of the soluble polysulfide intermediates could lead to a severe self-discharge effect that hinders the development of lithium-sulfur batteries. In this paper, a battery separator has been prepared based on NiFe 2 O 4 /Ketjen Black (KB) modification by a simple method to solve the shuttle effect and improve the battery performance. The as-modified separator with the combination of small-size KB and NiFe 2 O 4 nanoparticles can effectively use the physical and chemical double-layer adsorption to prevent polysulfide from the shuttle. Moreover, it can give full play to its catalytic effect to improve the conversion efficiency of polysulfide and activate the dead sulfur. The results show that the NiFe 2 O 4 /KB-modified separator battery still maintains a discharge capacity of 406.27 mAh/g after 1000 stable cycles at a high current density of 1 C. Furthermore, the coulombic efficiency remains at 99%, and the average capacity attenuation per cycle is only 0.051%. This simple and effective method can significantly improve the application capacity of lithium-sulfur batteries.