Preparation and properties of protein-derived carbon-modified CoS₂ applied to high-performance lithium-sulfur battery

In this study, we utilized egg white as a carbon source and sublimated sulfur as a source to synthesize the carrier material with carbon nanosheet framework-modified CoS2 nanoparticles (CoS2@C) through a one-step method. We investigated the effect of temperature on the material's structure and chemical composition and the impact of the carrier material on the electrochemical performance of lithium-sulfur batteries. The results reveal that CoS2@C-600 synthesized at 600 degrees C exhibits an exceptional three-dimensional carbon nanosheet structure with well-defined crystallinity for CoS2. The three-dimensional carbon sheet framework possesses abundant porous structures and high conductivity, providing ample space for sulfur accommodation and physically inhibiting the dissolution of polysulfides. Additionally, electrochemical tests demonstrate that the material exhibits remarkable rate capability and cycling performance. At a current density of 0.5 A/g, the initial discharge-specific capacity reaches 1407 mAh/g, and after 100 cycles, the specific capacity remains at 824 mAh/g. Even under high current conditions of 5 A/g, the specific capacity is maintained at 256 mAh/g. The carrier material, possessing a well-designed structure and an efficient lithium polysulfide electrocatalyst, effectively improves the cycling stability and enhances the rate performance of lithium-sulfur batteries.