锂离子电池正极材料的热稳定性

Thermal Stability of Cathode Materials of Lithium-Ion Battery

运用热分析方法定性研究了固态LiClO4和LiClO4电解液的热稳定性能,进而对比分析了3种常见锂离子电池正极材料LiNi0.85Co0.15O2,LiMn2O4和LiFePO4的热稳定性能.结果表明,在200~250℃温度范围内,LiClO4电解液不会影响反应体系.充电状态下,Li0.18Ni0.85Co0.15O2与电解液发生反应的温度集中在215℃左右;Li0.15Mn2O4与电解液发生反应的起始温度约为220℃,主要反应集中在250℃左右;Li0.17FePO4与电解液反应主要集中在230℃,但起始反应温度要高于Li0.15Mn2O4,显示出更好的热稳定性.因此,3种材料热稳定性由强到弱的顺序为：LiFePO4,LiMn2O4,LiNi0.85Co0.15O2.

The thermal stabilities of solid LiClO4 and LiClO4 electrolyte were studied by thermal analytic methods.Then we discussed the thermal stability of three common cathode materials using differential scanning calorimetry（DSC） method,including LiMn2O4,LiNi0.85Co0.15O2 and LiFePO4.In the range of 200-250 ℃,LiClO4 electrolyte did not affect the system.Li0.18Ni0.85Co0.15O2,Li0.15Mn2O4 and Li0.17FePO4 reacted with LiClO4 electrolyte mostly at 215,250 ℃ and 230 ℃ in the charged states,respectively.But the onset temperature of Li0.17FePO4 reacted with LiClO4 electrolyte was more positive than that of Li0.15Mn2O4.These results indicate that the order of the thermal stability was： LiFePO4LiMn2O4LiNi0.85Co0.15O2.