Construction of flower-like Ni-Cu@C/HC nanoparticles capable of inhibiting polysulfide shuttling for high-performance lithium-sulfur batteries

[Display omitted] •Synergistic effect of Ni-Cu@C and HC achieves polysulfides adsorption and anchoring.•Modified separator’s influence on discharge curves was first explored using COMSOL.•Polysulfides and Li+ diffusion were simulated to elucidate voltage change mechanism.•The GITT test with long-standing time (7200 s) elucidated the capacity loss mechanism.•High capacity was achieved by assembling a pouch cell with Ni-Cu@C/HC separator. High-performance lithium-sulfur (Li-S) batteries show high energy density while the commercialization process has been hampered by the shuttle effect. Herein, separators with flower-like nickel-copper alloy (Ni-Cu) nanoparticles loaded on hard carbon (HC) were designed to alleviate the polysulfide shuttle. The lithium-ion (Li+) diffusion coefficients and Tafel slopes of the three separators were calculated, demonstrating that Ni-Cu@C/HC can significantly accelerate polysulfides conversion. The separation modification layer’s influence on the discharge curve was first explored using COMSOL software under linear dimensions. The lithium polysulfides (LiPSs) reaction behavior and Li+ diffusion behavior were simulated, and the voltage change mechanism of the discharge curve was elucidated. The effect of Ni-Cu@C on Li2S conversion was investigated using Galvanostatic Intermittent Titration Technique and Li2S deposition experiments. The Ni-Cu@C/HC separator constructed in this work has multiple catalytic sites and catalytic core for LiPSs, which can significantly boost the polysulfides conversion and provide a good Li+ diffusion environment, contributing to the production of high-performance Li-S batteries.