Facile Synthesis of Sulfur–Polypyrrole as Cathodes for Lithium–Sulfur Batteries

Graphical To the grindstone : A sulfur–polypyrrole (S-PPy) composite is synthesized by a facile ball-milling route, in which PPy has been prepared through a self-degrading template method. Owing to the interstitial structure of S-PPy and multiple effects of PPy, S-PPy possesses a high discharge capacity, good cycling stability, and good rate performance (see figure; DME=1,2-dimethoxyethane, DOL=1,3-dioxolane). To explore the potential application of lithium–sulfur batteries (LSBs) in the emerging electric vehicle market, sulfur–polypyrrole (S-PPy) is prepared by a facile ball-milling route, in which polypyrrole is synthesized by using ferric chloride as an oxidant in a self-degrading template method. Compared with sulfur, S-PPy possesses a higher discharge capacity, much better cycling stability, and better rate performance. At a current density of 200 mA g −1 , the discharge capacity of S-PPy is maintained at 675 mA h g −1 after 150 cycles, and even at a current density of 1675 mA g −1 , the retained discharge capacity is still 617 mA h g −1 after 100 cycles. The retained discharge capacity of pure sulfur, however, is only 150 mA h g −1 after 150 cycles at a current density of 200 mA g −1 . These results indicate that S-PPy, with its facile, low-cost, and eco-friendly synthesis, could be a potential cathode material for LSBs.