Comparison of the thermal stability of lithiated graphite in LiBOB EC/DEC and in LiPF6 EC/DEC

Accelerating rate calorimetry (ARC) has been used to compare the thermal stability of lithiated mesocarbon microbeads (MCMB) (Li0.81C6) in the presence of saturated lithium bis(oxalato) borate (LiBOB) in ethylene carbonate (EC)/diethyl carbonate (DEC) (about 0.8 M) and LiPF6 in EC/DEC (1.0 M). The exothermic reaction between lithiated MCMB and LiBOB EC/DEC electrolyte does not proceed strongly until about 170degreesC but it begins at about 80degreesC for lithiated MCMB in LiPF6 EC/DEC. We believe that LiBOB electrolytes offer significant advantages for cell abuse tolerance compared to LiPF6 electrolytes, at least as far as anode/electrolyte reactions are concerned. (C) 2003 The Electrochemical Society.