SBIR-STTR Award

The objective of the proposed research is to limit voltage delay, anode corrosion during intermittent usage and to increase the current capability and capacity of li/soc1(2) cells through the use of new electrolyte salts. The principles used will be those which have succeeded in the past, namely, by limiting the concentration of the electrolyte salt and by using the lithium salts of large anions which either cannot exchange with the lithium chloride solid electrolyte interphase, or have reduced ability to exchange. However, the new salts will not be subject to oxidation by the relevant and will not be expensive. The work will include the synthesis and analysis of the new salts, measurements of solubilities and preliminary evaluation of capacity, rate capability, and voltage delay, using AA cells, comparing the new electrolytes with 1.8m lialc14/socl(2) fresh and after storage at 71 deg C for one month.

The main objective of this effort will be to improve the performance of lithium/thionyl chloride primary cells in the six areas identified as being the chief Navy needs for improvement specifically in these power sources. In an exploratory development effort, wound c size, hermetically sealed cells will be used to investigate whether changes in the composition of the electrolyte, cathode, or separator will result in improvements in the needed areas. These areas include voltage regulation, low temperature performance, rapid activation after storage, better storage capability, increased energy output, and safety. The baseline or control cells will be built in accordance with the current design for captor c size cells. The test cells will include electrolytes prepared with new salts discovered during the Phase I effort, cathodes prepared with different carbons and catalytic substances, and alternative separator materials. The test conditions will include fresh cells and cells stored at temperatures as high as 71 deg c. For up to 90 days and activation at temperatures as low as -30 deg c. And rates as high as 10 na/cm2. The data to be reported will be the lowest potential reached during activation, the time to recover to two and to three volts, discharge profiles, and capacities to three and to two volts.