Thermal stability of ethylene carbonate reacted with delithiated cathode materials in lithium-ion batteries

Confinement tests are implemented for measuring exothermic behaviors of eight delithiated or non-lithiated cathode materials mixed with ethylene carbonate (EC) which are commonly used in lithium-ion batteries. Eight delithiated and non-lithiated cathode materials, namely lithium cobalt oxide (LixCoO2), nickel oxide (NiO2), lithium nickel oxide (LixNiO2), lithium nickel cobalt oxide (LixNi0.8Co0.2O2), manganese oxide (Mn2O4), lithium manganese oxide (LixMn2O4), cobalt oxide (Co3O4) and iron phosphate (FePO4)are mixed with EC under a programmed rate of heating, respectively. Trajectories of temperature and pressure are measured simultaneously in the confined apparatus. Characteristics of thermal runaway such as onset temperature, maximum temperature, maximum pressure, maximum self-heat rate, etc., are assessed. The ranking of thermal stabilities of delithiated cathode and non-lithiated materials with EC is discussed and compared.