Analysis of secondary lithium cells with sulfur dioxide based electrolytes

Recent developments in lithium rechargeable cells using liquid SO ₂-based electrolyte have led to the demonstration of 100-200 cycles at practical energy densities of over 100 Wh/kg in flat-plate cells. Analytical studies were conducted to confirm the discharge mechanism and to explore the effects of using various cycling voltage limits in Li/CuCl₂ cells. These cells have excellent shelf-life potential and can utilize either a copper chloride cathode or, with appropriate choice of high surface area carbon and electrolyte composition, the SO₂ itself can provide the cathode material. Experimental cells with a flat electrode design were used to study the cell chemistry and cycling performance. The behavior of Li/CuCl₂ cells cycled with various voltage limits is summarized. To gain an understanding of how materials interact in Li/CuCl₂ cells, hermetically sealed glass cells were prepared containing cell components in various combinations. These materials were soaked at room temperature for three weeks and examined with X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and chemical analyses for the presence of copper. The results are given. Some design considerations which affect safety and performance in Li/SO₂ cells were also investigated