Insight into sulfur-rich selenium sulfide/pyrolyzed polyacrylonitrile cathodes for Li-S batteries

As promising cathode materials in lithium sulfur batteries, sulfur-rich selenium sulfide (SexS1-x)/pyrolyzed polyacrylonitrile (pPAN) composites, denoted as SexS1-x@pPAN, can effectively alleviate the problem of polysulfide dissolution and deliver reliable performances. Nevertheless, the material properties essential to the electrochemical performance of SexS1-x@pPAN still require further studies. Herein, SexS1-x@pPAN materials were preparedviaa simple calcination strategy using the commercial selenium sulfide (SeS2) as the sulfur and selenium source. SexS1-x@pPAN composites with different active material contents were successfully synthesized by controlling the calcination temperature, and thus the reaction kinetics of the lithium-sulfur battery could be precisely manipulated. The electrochemical performance of the as-prepared SexS1-x@pPAN materials was systematically investigated, and a temperature dependence of the specific capacity was observed. Consequently, the optimized synthetic conditions were determined, resulting in the assembled Se0.38S0.62@pPAN-450 degrees C full cell showing a high areal capacity of 2.62 mA h cm(-2)after 200 cycles with a high Se(0.38)S(0.62)loading of 4.53 mg cm(-2)in ether electrolyte. Furthermore, Se0.38S0.62@pPAN-450 degrees C exhibited excellent battery performance in both carbonate and ether electrolytes.