A nano-structured and highly ordered polypyrrole-sulfur cathode for lithium–sulfur batteries

A tubular polypyrrole (T-PPy) fiber is synthesized as a conductive matrix for the cathode of lithium–sulfur secondary battery. The sublimed sulfur is incorporated with the T-PPy by a co-heating process. The location and the content of sulfur show a significant effect on the electrochemical behavior of the composite. A reversible capacity of ca. 650 mAh g−1 is maintained for over 80 cycles for the S/T-PPy composite with 30 wt.% sulfur. The enhanced conductivity, the favorable distribution of the nano-sized sulfur in the T-PPy and the stable retention of polysulfides lead to the improvement of the cycling stability of the sulfur based electrode.