Abstract: Spinel LiMn2O4 cathode material doped with Cr3+ and F－ was prepared by solid-state reaction，and the material was modified by coating Al2O3 on its surface. The morphology and structure were characterized with scanning electron micrograph and X-ray diffraction，and the electrochemical properties were studied with charging-discharging test and A.C impedance test. The results showed that both materials doped with Cr3+ and F- and coated with Al2O3 had a spinel structure. With increasing level of doping and coating，their initial discharging capacity reduced，but their cycling performance was greatly improved. The 1st discharging capacities of LiMn2O4，LiMn1.9Cr0.1O3.9F0.1 and LiMn1.9Cr0.1O3.9F0.1/coated 0.3%Al2O3 were 125.3，117.5 and 113.7mA·h·g－1 respectively，after 25 cycles，their capacity retentions were 82.7%，91.5% and 93.6% respectively. When cycling at 55℃，the electrochemical properties of the material coated with Al2O3 was the best，its discharging capacity and capacity retention after 25 cycles were 104.2 mA·h·g－1 and 92.1% respectively.

摘要： 用固相法制备了Cr3+和F－同时掺杂的尖晶石型LiMn2O4正极材料，并对掺杂材料进行氧化铝表面包覆改性，用扫描电子显微镜和X射线衍射研究了材料的表面形貌和晶体结构，用充放电实验和交流阻抗技术测试了材料的电化学性能。结果表明：LiMn2O4在掺杂Cr3+和F－及表面包覆氧化铝后仍为尖晶石型结构，随掺杂和包覆量的增加，材料首次放电容量降低，但循环性能明显改善，其中未掺杂、掺杂量为0.10和表面包覆0.3%的氧化铝的材料室温首次放电容量分别为125.3 mA•h/g、117.5 mA•h/g和113.7 mA•h/g，循环25次后容量保持率分别为82.7%、91.5%和93.6%，而55 ℃下25次循环后放电容量及其保持率以表面包覆氧化铝的最佳，分别达到104.2 mA•h/g和92.1%。