Preparation of Mesoporous Carbon/Sulfur Composite Loaded with ZnS and Its Property for Lithium-sulfur Batteries

With the aim to obtain high performance cathode materials for lithium-sulfur batteries, composite of mesoporous carbon (MC) loaded with ZnS (ZnS/MC) was prepared through ultrasonic dispersion and heat treatment. The as-prepared composite was blended with elemental sulfur by heating, then cathode materials (ZnS/MC/S) was obtained. The ZnS/MC composite was characterized by XRD, SEM, EDS and N-2 adsorption-desorption isotherms. The results showed that ZnS particle was uniformly loaded to the surface of MC through ultrasonic dispersion when content of ZnS was less than 17wt%. ZnS nanoparticles aggregated to form sphalerite ZnS by heat treatment or increasing content of ZnS. Cyclic voltammetry test showed that ZnS accelerated the oxidation process of polysulfides. Charge/discharge tests indicated that the initial discharge specific capacity was 1354.6 mAh/g, while the coulombic efficiency of the first charge and discharge was 98.7%. The capacity still remained 650 mAh/g after 50 cycles.