Preparation and electrochemical properties of polysulfide polypyrrole

A novel cathode material, polysulfide polypyrrole was successfully designed and synthesized for high-energy lithium–sulfur secondary batteries. The product was characterized by FT-IR, element analysis and DSC. Character results show that the polymer was obtained with polypyrrole as backbone and S–S side groups attached to it. Polypyrrole backbone in this polymer was used not only as container but also as conductivity passage. Cycle performances of the polymer was examined as active cathode material in lithium batteries, charge–discharge experimental results indicate that the polymer has a specific capacity of 515 mAh g−1 at the first cycle and 452 mAh g−1 at the 20th cycle. The improved cycle properties compared to other polymer disulfides and polysulfide polymers supply a good foundation for practical application of this material in rechargeable lithium batteries.

► Polysulfides polypyrrole (SPPy) is a conducting polymer with high capacity.
► The SPPy contains 2 active structure units which could insert lithium.
► The way to combine 2 or more active material together might be a good way out.