The organic solvent DMC is an important factor causing the instability of electrolyte, and the higher the DMC content, the more unstable the electrolyte.

　　The electrolytes of EC+DEC, EC+DMC, PC+DEC and PC+DMC mixed solvents dissolved in 1mol/L LiPF6 were studied in a closed container by DSC. It was found that the electrolyte containing DMC was more prone to react than the electrolyte containing DEC.

　　The electrolyte can make the positive electrode react at a lower temperature, and different solvents and lithium salts in the electrolyte are suitable for different positive electrode materials.

　　The exothermic reaction between Li0.5CoO2 and LiMn2O4 charging positive electrode and electrolyte was studied by ARC and XRD methods respectively. The research shows that for Li0.5CoO2 powder, decomposition reaction occurs when the temperature is higher than 200 ℃, and oxygen is released, while the exothermic reaction with EC/DEC solvent occurs at 130 ℃. After LiPF6 is added to the solvent, the reaction is inhibited. For LiMn2O4 material, the crystal transformation occurs at 160 ℃ and exothermic, and the presence of solvent has no effect on this reaction. After adding LiPF6 to the electrolyte, the reaction between LiMn2O4 and the electrolyte will intensify with the increase of LiPF6 concentration.

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