Influence of trace components on the physical and electrical properties of the solid electrolyte interphase in lithium/thionyl chloride cells

摘要

Lithium/ thionyl chloride cells designed for down-hole instrumentation have been discharged at 1000C. by alternating between 3.5 mA/cm{sup}2 for 30 minutes and open circuit for 4 minutes, until the cells are exhausted. Gradual recovery fromvoltage delay, even following open circuit stand of only four minutes, has indicated the formation of heavy salt films through extensive lithium corrosion.The presence of iron, even at concentrations as low as 20 mg/L, can increase lithium corrosion during discharge. The inclusion of non-transition metal elements at concentrations between 10 and 200 milligrams per liter has been found to profoundly affectthe physical and conductive properties of the lithium chloride salt film, and in particular, at 100°C will increase both the capacity and running potential and inhibit iron from causing lithium corrosion.