Catalytic nickel nanoparticles embedded on ZIF-8 backbone for accelerating polysulfide conversion in lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) are considered one of the most promising next-generation energy storage systems owing to their ultrahigh energy density and discharge-specific capacity. However, the poor conductivity of active sulfur and the shuttle effect caused by lithium polysulfides (LiPSs) lead to a rapid decrease in the charge and discharge capacities of batteries, seriously hindering their further development. In this study, metallic nickel nanoparticles are successfully introduced into a nitrogen-rich porous carbon framework (Ni-CN) material using a solvothermal method. The addition of metallic nickel improves the adsorption and conversion ability of the CN towards polysulfides, thereby improving the reaction kinetics. The symmetrical battery assembled with Ni-CN exhibits a higher current response, indicating that the nickel nanoparticle catalyst has excellent catalytic ability. The results indicate that the battery assembled with sulfur-loaded Ni-CN (S@Ni-CN) has excellent cycling performance, with a maximum discharge specific capacity of 1295.3 mAh/g at 0.1C and a discharge specific capacity of 906.7 mAh/g after 200 cycles, with an average capacity decay of about 0.15 % per cycle. In contrast with traditional porous carbon electrodes, Ni-CN demonstrates superior adsorption capacity for polysulfides and enhances the conversion rate of these compounds, leading to a more efficient utilization of sulfur.