A comparative study of the thermal stability of charged cathodes, by accelerating rate calorimetry, found that cathodes based on Li3CrMnO5 were less thermally reactive with a conventional electrolyte solution, 1M LiPF6 in 3:7 EC/DEC, than cathodes containing LiCoO2. Arrhenius parameters of activation energies and frequency factors were determined from forced heating experiments. The exothermic reactions of Li3CrMnO5 cathodes were investigated as a function of state of charge, electrolyte solution volume and electrolyte salt concentration.