Low-Temperature Synthesis of a Sulfur-Polyacrylonitrile Composite Cathode for Lithium-Sulfur Batteries

Through a novel synthesis process, a novel sulfurized polyacrylonitrile (SPAN) composite, noted as DH-150-300-SPAN, was prepared and tested as cathode material for lithium sulfur (Li-S) batteries. The reported process involves two heating steps at low temperature. The first plateau at 150 degrees C melts elemental sulfur, while the second, at 300 degrees C, produces the cycling of polyacrylonitrile, and incorporates sulfur to the cyclic polymeric structure. A fully morphological and electrochemical characterization was carried out. The SPAN composite contains (38.3 +/- 0.2) % S. Li-S batteries assembled using these cathodes have shown good performance, reaching high and stable capacity values, above 1000 mAh gS-1 after 150 cycles at 0.1 C. This is the first time that stable cycling is achieved for a SPAN composite synthesized at such low temperatures and for short heating treatments. Our work describes an easy route to prepare a promising candidate for cathode material of Li-S batteries by using a low-cost process and low-cost materials.