Effects of solvents and salt on the thermal stability of lithiated graphite used in lithium ion battery

The thermal stability of lithiated graphite in the presence of solvents, electrolytes and LiPF6 salt was studied using C80 micro-calorimeter. The presence of cyclic carbonates or linear carbonates increases the activity of LixC6-solvent coexisting system, especially for the LixC6-linear carbonates one. LiPF6 was detected that it increases the activity greatly of its coexisting system with lithiated graphite. The coexisting system of LixC6 with the electrolyte of LiPF6/ethylene carbonate + diethyl carbonate shows less thermal stability, which is attributed to the activity between diethyl carbonate and LixC6. This also agrees with the experiment result of LixC6-diethyl carbonate coexisting system. (C) 2009 Elsevier B.V. All rights reserved.