Wang QS, Sun JH, Chen CH (2006b) Thermal stability of LiPF6/EC+DMC+EMC electrolyte for lithium ion batteries. Rare Metals 25, 94-99. [In English]
lithium ion battery; electrolyte; thermal stability; C80 micro; calorimeter; alkyl carbonate; dimethyl carbonate; cells; decomposition; mechanism; behavior; safety; spectroscopy;
Abstract: The thermal stability of lithium-ion battery electrolyte could substantially affect the safety of lithium-ion battery. In order to disclose the thermal stability of 1.0 mol center dot L-1 LiPF6/ethylene carbonate (EC) + dimethyl carbonate (DMC) + ethylmethyl carbonate (EMC) electrolyte, a micro calorimeter C80 micro calorimeter was used in this paper. The electrolyte samples were heated in argon atmosphere, and the heat flow and pressure performances were detected. It is found that LiPF6 influences the thermal behavior remarkably, with more heat generation and lower onset temperature. LiPF6/EC shows an exothermic peak at 212 degrees C with a heat of reaction - 355.4 J center dot g(-1). DMC based LiPF6 solution shows two endothermic peak temperatures at 68.5 and 187 degrees C in argon filled vessel at elevated temperature. EMC based LiPF6 solution shows two endothermic peak temperatures at 191 and 258 degrees C in argon filled vessel. 1.0 mol center dot L-1 LiPF6/EC + DMC + EMC electrolyte shows an endothermic and exothermic process one after the other at elevated temperature. By comparing with the thermal behavior of single solvent based LiPF6 solution, it can be speculated that LiPF6 may react with EC, DMC and EMC separately in 1.0 mol center dot L-1 LiPF6/EC + DMC + EMC electrolyte, but the exothermic peak is lower than that of 1.0 mol center dot L-1 LiPF6/EC solution. Furthermore, The 1.0 mol center dot L-1 LiPF6/EC + DMC + EMC electrolyte decomposition reaction order was calculated based on the pressure data, its value is n = 1.83, and the pressure rate constants k(p) = 6.49 x 10(-2) kPa center dot (-0.83) center dot min(-1).