SBIR-STTR Award

This project will evaluate the low temperature (to -55 degrees C) performance of the Li/CuCl*2* and Li/LixCo0*2* rechargeable cells with SO*2* electrolytes to determine if one of these battery systems should be developed as a power source for aircrew survival-rescue equipment. The excellent cycle life and specific energy (e.g. 200 deep cycles at 165 Whr/Kg), wide operating temperature range, low self-discharge rate and ruggedness make the Li/CuCl*2* system particularly attractive for such an application. The approach in Phase I will be to characterize the low temperature 1.1 mA/cm^2 continuous discharge and 10-50 mA/cm^2 pulse discharge performance of 80 mAhr size laboratory cells at 23, -20 and -55 degrees C and then to evaluate the performance again after a number of innovative improvements to the positive electrode, electrolyte and cell design. Innovations that will receive particular emphasis will include reducing the particle size of the positive electrode active materials and conductive additives, modifying the crystal structure or purity of the active material and changing the electrolyte salt and adding volatile cosolvents. The construction and testing of rechargeable cells with 7.6 cm diameter bipolar electrodes will be undertaken to evaluate the merits of the bipolar electrode design as a means to increase the volumetric energy density for low temperature applications.

Keywords:
RECHARGEABLE BATTERY LITHIUM BATTERY NON-AQUEOUS BATTERY SECONDARY BATTERY BATTERY LITHIUM

This project will improve the low temperature (to -55 degrees C), pulse discharge and reliability of the Li/Cucl2/So2 electrolyte rechargeable battery system to demonstrate the value of the system for aircrew survival rescue equipment and other Air Force applications. The excellent cycle life and specific energy (e.g. 200 deep cycles at 165 Whr/kg), wide operating temperature range, low self discharge rate and ruggedness make the Li/CuCl2 system particularly attractive for such applications. During Phase I it was shown that changing a CuCl2 morphology parameter by a factor of four increased the discharge capacity by an average of 86% from -20 to -50 degrees C at 1.0 mA/cm2. The approach for Phase II will involve investigating whether the performance can be increased by changing the morphology parameter by a further factor of 10 to 4000. As part of a technology development task, the electrolyte, cell design and CuCl2 fabrication process will be developed to improve the energy density, high rate (to mA/Cm2) pulse discharge performance and cell reliability. During two cell development tasks, D and 0.5D size cells and 6.7 cm dia bipolar batteries will be constructed and cycle life and other tests carried out.