Nonflammable Lithium-ion Battery Electrolytes Capable of Extended Operational Temperature Ranges

The U.S. Air Force requires that rechargeable lithium ion (Li-ion) batteries operate at the extremes of a thermal envelope that cannot be met with present-day battery technology. Based on some new materials developed by us and some preliminary resultsobtained with them, we believe that a new family of non-flammable electrolytes may be formulated so as to allow Li-ion battery cycling at temperatures as low as -50¿C and as high as 80¿C with good capacity retention. During Phase I we will synthesize anumber of new salts and formulate them with various solvents. The resulting electrolytes will be characterized in respect to ionic conductivity at various temperatures, electrochemical stability, and flammability. Our best non-flammable electrolyteformulations will be subjected to cycling in Li-ion cells at the aforementioned temperature extremes. The development of a new family of non-flammable electrolytes that allow Li-ion batteries to cycle with good capacity over a 130¿C thermal window willfulfill a broad spectrum of military and civilian power source requirements. In addition to powering weapons systems under climatic extremes, such advanced electrolytes would also enable the development of safer Li-ion batteries for consumer electronicsand hybrid electric vehicle applications.