The thermal behaviors of FeF3 cathode in 1 mol dm(-3) LiPF6/methyl difluoroacetate (MFA) electrolyte are quantitatively investigated by differential scanning calorimetry. MFA-based electrolyte shows great thermal stability without heat generation up to 500 degrees C. The cycled electrodes are studied and find to become more thermally stable after lithiation. Furthermore, the lithiated electrode shows a superior thermal stability in the electrolyte compared to the delithiated electrode. Although the heat generated by the mixtures of cycled electrodes and MFA-based electrolyte is larger, the lithiated and delithiated electrodes coexisted with MFA-based electrolyte are about 140 and 230 degrees C higher than that of EC + DMC-based electrolyte, respectively. Therefore, the safety of FeF3 battery is enhanced by using MFA-based electrolyte instead of EC + DMC-based electrolyte. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.