Composite separators modified with metal sulfide-loaded carbon nanosheet via expansion technology for mitigating shuttle effect.

Schematic diagrams illustrating the principle of improving batteries performance by modifying separator with NSC/PP and MS@NSC/PP. [Display omitted] • Expanding aids in distributing metal sulfides uniformly via impregnation. • Carbon material covers large pores and improves interface impedance. • Composite separators anchor polysulfides and enhancing reaction kinetics. Lithium-sulfur (Li-S) batteries, renowned for high energy density and abundant sulfur reserves, are recognized as a research hotspot. However, the commercial implementing of Li-S batteries is confronted with scientific and technical challenges, including the shuttle effect resulting in low active material utilization, and slow reaction kinetics leading to poor cycle stability. To optimize the structure and composition of carbon composite materials based to meet the application requirements for long cycle life and high utilization of active substances has become the focus and difficulty. In this study, a composite separator MS@NSC/PP by coting nanosheet carbon (NSC) material loaded with amounts of metal sulfide (MS) was prepared via expansion technology and sulfurization impregnation. The combination of two processes greatly increases interaction area between MS@NSC and polysulfides and achieves uniform loading of MS, fully enhancing the mitigation of shuttle effect through strong chemical adsorption, and further hastening the conversion reaction of polysulfides deposited on the surface. Compared with NSC/PP and NiS 2 @NSC/PP separators, the batteries with CoS 2 @NSC/PP separator display a high initial discharge capacity of 1135 mAh g−1 at 0.2C, maintaining more improved cycle stability at 2C. [ABSTRACT FROM AUTHOR]