Preparation and electrical properties of lithium–sulfur-composite polymer batteries

The lithium/sulfur batteries consisted of a composite cathode, a polymer electrolyte, and lithium anode. The composite cathode was made from active sulfur (or lithium sulfide), carbon black, poly(ethylene oxide) (PEO), LiClO4, and acetonitrile. And the polymer electrolyte (PE) was made of gel-type linear PEO with tetra(ethylene glycol dimethyl ether). The open circuit voltage (OCV) of the Li–S battery was about 2.5 V. The Li–S battery showed two reduction peaks and one oxidation peak, which correspond to those of the cell made of lithium sulfide as active material and it had an irreversible kinetic mechanism, which was supported by the charge–discharge and cyclic voltammetry (CV) experiments as a function of current load and sweep rate. When iron (Fe) powder was added to the composite cathode, its effect on the electrochemical property of the cell was investigated. This cell showed higher specific capacity and longer cycle life than the Li–S battery, and several possible explanations for the effect of Fe in Li–S battery has been presented.