The thermal behavior and structural changes of representative types of lithiated graphitic materials were investigated in solutions comprising ethylene carbonate (EC), ethylmethyl carbonate (EMC), dimethyl carbonate (DMC) and LiPF6. We show that the protective films formed on intercalated graphite electrodes upon cathodic polarization are stable in these electrolyte solutions up to similar to 80 degrees C, in DSC experiments. Upon increasing the temperature, between 80 and 120 degrees C, reactions of the surface films with solution species take place and the level of the graphite lithiation is reduced. After destruction of the surface films on lithiated graphite at higher temperatures >120 degrees C, solvent molecules diffuse into the graphite particles and interact with Li ions therein thus forming reduction products. The later decompose upon further heating at temperatures >200 degrees C, with the formation of gaseous products. This results in an internal pressure within the graphite particles that causes their partial exfoliation in an endothermic process. While the protective surface films on the lithiated graphite are removed from the particles in the course of the thermal reactions, we have indications that surface films on fully delithiated graphite do not react with the electrolyte solution at least up to 200 degrees C. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3598173] All rights reserved.