"CYCLE LIFE SENSOR FOR RECHARGEABLE LITHIUM BATTERIES"

THIS PROPOSAL ADDRESSES THE PROBLEM OF CHARACTERIZING THE STATE OF A RECHARGEABLE LI BATTERY AS A FUNCTION OF CYCLE LIFE HISTORY. BECAUSE ALL LI BATTERIES ARE HERMETICALLY SEALED, WE HAVE CHOSEN TO EVALUATE THE AMOUNT AND DISTRIBUTION OF LI-ELECTROLYTE DEGRADATION PRODUCTS IN SITU BY THE APPLICATION OF ELECTROANALYTICAL TECHNIQUES AT MICROELECTRODES IMBEDDED IN THE CELL PACKAGE. TWO DIFFERENT ELECTROLYTES WITH VARYING DEGREES OF REACTIVITY TOWARD THE LI ELECTRODE WILL BE ASSESSED. ELECTROANALYTICAL DATA ON INTERFACIAL REACTION PRODUCTS AS WELL AS THOSE SPECIES SOLUBLE IN THE BULK WILL BE COLLECTED AND DIGITALLY MANIPULATED SO AS TO GENERATE REACTIVITY PROFILES/SIGNATURES OF A GIVEN ELECTROLYTE AT A GIVEN TIME IN ITS CYCLING HISTORY. THE GOAL OF THIS PROJECT IS TWO-FOLD: TO ASCERTAIN WHICH CHEMICAL DEGRADATION PRODUCTS ULTIMATELY INFLUENCE CELL SAFETY AND CYCLE LIFE; AND TO DEVELOP AN IN SITU ELECTROANALYTICAL METHOD WHICH SPECIFIES THE STATE OF A CELL AT ANY POINT ALONG ITS CYCLE LIFE.