The cathode material pyrite (FeS 2 ) (core) was coated with 2.5, 5.0, 7.5, and 10.0 wt% CoS 2 (shell) (denoted as FeS 2 @CoS 2 ) by the hydrothermal method and a subsequent heat-treatment to form composites with enhanced thermal stability and electrochemical performance. Importantly, results indicate indicated that CoS 2 particles with a complete crystal structure had been successfully coated on the FeS 2 surface. The sample coated with the optimal amount of CoS 2 , which was determined to be 7.5 wt%, showed the highest thermal decomposition temperature (610.6 • C) and excellent specific capacity (as high as 320 mA h g −1 at 520 • C and 200 mA cm −2 at a cutoff voltage of 1.6 V), in compared to that of pure FeS 2 (551.3 • C, 240 mA h g −1 ). Because CoS 2 is an excellent electrical conductor, the surface of FeS 2 is modified by CoS 2 , which leads to the change of the microstructure of FeS 2 surface, which enhances the intercalation of ionic electrolyte and enhances the electrical conductivity of FeS 2 . In the meantime, CoS 2 has high thermal stability and exhibits low solubility in the molten electrolyte, which reduces the elemental sulfur loss of FeS 2 during discharge and thereby increases the electrochemical capacity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.