Improved Power Source for Doubling the Exchange Time Interval of LLC. LDRD Funded Project

摘要

This LDRD project attempts to use novel electrochemical techniques to understand the reaction mechanism that limits the discharge reaction of lithium CF(sub x) chemistry. If this advanced component development and exploratory investigations efforts are successful we will have a High Energy Density Li Primary Battery Technology with the capability to double the run time in the same volume, or provide the same energy in a much smaller volume. These achievements would be a substantial improvement over commercial Li/Thionyl chloride battery technology. The Li(CF(sub x))(sub n) chemistry has the highest theoretical energy (and capacity) and hence very attractive for long life battery applications. However, the practical open circuit voltage (OCV) is only 3.2 V which is (approx)1.3 V lower than the thermodynamic cell voltage (for an in depth explanation of the voltage depression refer to 'Introduction'). The presence of intermediate has been invoked to explain the lower OCV of the cell. Due to the reduction in cell voltage the cell out put is reduced by (approx)40%. To account for the initial voltage loss a mechanism has been proposed which involves the formation of a ternary compound (like C(LiF)(sub x)). But neither its presence nor its nature has been confirmed. Our work will seek to develop understanding of the voltage depression with a goal to produce a primary battery with improved properties that will have significant impact in furthering advancements.