Dual-Constrained Sulfur in FeS₂@C Nanostructured Lithium-Sulfide Batteries

Irreversible consumption of sulfur aroused from shuttle reaction is the major challenge for liquid electrolyte lithium–sulfur batteries, although various sulfur-based cathodes have been designed. In this work, strict constraint of sulfur to eradicate the polysulfide shuttling is realized in the nanostructure of carbon-coated metal sulfides instead of pure sulfur cathodes. The nanoparticles are composed of a carbon shell and iron disulfide core (FeS2@C), fabricated by the plasma evaporation method and postsulfurization. The Fe–S bonds in FeS2 chemically attract the sulfur atoms during their lithiation reaction, while the carbon shell physically blocks the sulfur loss within the enclosed construction. Owing to the remarkable dual constraint of S, the FeS2@C cathode delivers a stable specific capacity of 862 mA h g–1 after 300 cycles. The assembled battery cells exhibit stable electrochemical performance when they are operated safely in the temperature range from 60 to −25 °C.