Thermal stability of propylene carbonate and ethylene carbonate–propylene carbonate-based electrolytes for use in Li cells

The thermal stability of mixed-solvent electrolytes used in lithium cells was investigated by differential scanning calorimetry (DSC) through the use of airtight containers. The electrolytes used were propylene carbonate (PC) and ethylene carbonate (EC)+PC, in which was dissolved 1 M LiPF6, 1 M LiBF4, 1 M LiClO4, 1 M LiSO3CF3, 1 M LiN(SO2CF3)2, or 1.23 M LiN(SO2CF3)(SO2C4F9). The influence of lithium metal or the Li0.5CoO2 addition on the thermal behavior of these electrolytes was also investigated. The peak temperature of PC-based electrolytes increased following the order of LiPF6