A composite of sulfur and polypyrrole-multi walled carbon combinatorial nanotube as cathode for Li/S battery

A core/shell structure of polypyrrole (PPy) and multi walled carbon tube (MWCNT) composite is proposed. The PPy is introduced to the surface of MWCNT by an in situ polymerization of pyrrole with FeCl3 as the oxidizing agent. The structures of the PPy-MWCNT composites are analyzed by Raman spectra. The surface area of the PPy-MWCNT composite increases with the increase of the PPy content in the composite. Adversely, the conductivity of the S/PPy-MWCNT decreases. The MWCNT provides the high electronic conductive network. Meanwhile, the PPy with high surface area ensures an uniform dispersion of the sulfur. As a result, S/PPy-MWCNT with 25 wt.% PPy shows the discharge capacity of 725.8 mA h g(-1) after 100 cycles. (C) 2012 Elsevier B.V. All rights reserved.