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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.

The lithium/sulfur (Li–S) batteries consist of a composite cathode, a polymer electrolyte, and a lithium anode. The composite cathode is made from elemental sulfur (or lithium sulfide), carbon black, PEO, LiClO4, and acetonitrile. The polymer electrolyte is made of gel-type linear poly(ethylene oxide) (PEO) with tetra ethylene glycol dimethyl ether. Cells based on Li2S or sulfur have open-circuit voltages of about 2.2 and 2.5 V, respectively. The former cell shows two reduction peaks and one oxidation peak. It is suggested that the first reduction peak is caused by the change from polysulfide to short lithium polysulfide, and the second reduction peak by the change from short lithium polysulfide to lithium sulfide (Li2S, Li2S2). The cell based on sulfur has the same reduction mechanism as that of Li2S, which is caused by the multi process (first and second reduction) of lithium polysulfide. On charge–discharge cycling, the first discharge has a higher capacity than subsequent discharges and the flat discharge voltage is about 2.0 V. As the current load is increased, the discharge capacity decreases. One reason for this fading capacity and low sulfur utilization is the aggregation of sulfur (or polysulfide) with cycling.