Synthesis and electrochemical properties of polypyrrole-coated poly(2,5-dimercapto-1,3,4-thiadiazole)

A new composite cathode active material, conductive polypyrrole (PPy)-coated poly(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT) was prepared as a thin film via the surfactant template (TFST) technique. The formation of the uniform and well-connected film on the surface of PDMcT particles was confirmed by Fourier transform infrared spectra (FT-IR) and transmission electron micrographs (TEM). By cyclic voltammetry and galvanostatic charge-discharge tests, the coated composite showed a better electrochemical performance than PDMcT, such as enhanced redox processes and improved coulumbic efficiency, etc. The electrical conductivity of the material reached to 10(-3) S cm(-1) and an initial discharge capacity of 250 mAhg(-1) was obtained. Moreover, it showed a slower fading of discharge capacity than PDMcT when used as cathode material in secondary lithium batteries with liquid electrolyte solution. (C) 2003 Elsevier Science B.V. All rights reserved.