| 摘 要： | A nano sulfur-based composite cathode material featured by uniform core@shell-structured sulfur@polypyrrole nanoparticles sandwiched in three-dimensional graphene sheets conductive network(S@PPy/GS) is fabricated via a facile solution-based method. The S@PPy nanoparticles are synthesized by in situ chemical oxidative polymerization of pyrrole on the surface of sulfur particles,and then graphene sheets are covered outside the S@PPy nanoparticles,forming a three-dimensional conductive network. When evaluating the electrochemical performance of S@PPy/GS in a lithium–sulfur battery,it delivers large discharge capacity,excellent cycle stability,and good rate capability. The initial discharge capacity is up to 1040 m Ah/g at 0.1 C,the capacity can remain 537.8 m Ah/g at 0.2 C after 200 cycles,even at a higher rate of 1 C,the specific capacity still reaches 566.5 m Ah/g. The good electrochemical performance is attributed to the unique structure of S@PPy/GS,which can not only provide an excellent transport of lithium and electron ions within the electrodes,but also retard the shuttle effect of soluble lithium polysulfides effectively,thus plays a positive role in building better lithium-sulfur batteries.
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