In Situ Study of Electrolyte Reactions in Secondary Lithium Cells

Reactions between nonaqueous electrolytes used in secondary lithium cells and lithium may produce gaseous products. We describe a variable volume device which is attached to a cell and controlled so that the cell pressure remains constant. Thus, we can accurately monitor the formation of gases from electrolyte reactions in cells as they are cycled. Experiments on Li / Li x MoS 2 cells using electrolytes such as 1 M LiAsF 6 in propylene carbonate and in sulfolane are presented and discussed. These are the first reported in situ measurements of gas evolution in secondary lithium cells.