SBIR-STTR Award

The proposed program relates to the identification of a mixed solvent electrolyte capable of extending the power density, cycle life and useful temperature range of a lithium secondary battery. Cells with electrolytes containing a mixture of a cyclic ether and an alkyl urea will be tested. The mixture has been chosen for evaluation because initial nmr data showed these two solvent types to have considerable electron cloud overlap when mixed in the proper proportions. Such overlap provides for higher chemical stability and solute solvation power. Successful completion of the program will result in the identification of a mixed solvent electrolyte which provide at least 2 ma/cm 2 performance over a broad temperature range (-40 deg to +71 deg c) of a lithium secondary cell) the mixture will also support ex_ tended cell cycling on storage. The program approach is to carry out cell cycle tests over a broad temperature range. Electrolyte de_ gradation will be followed by GC and nmr; anode surface characteristics will be determined by a technique based on the measurement of galvanostatic transients. The optimized electrolyte mixture will be tested in multielectrode sealed cells.