中文摘要：

锰酸锂正极材料在充放电循环过程中容量衰减严重,严重影响其大规模应用。针对其容量衰减严重的问题,通过固相制备出Li0.95Na0.05Mg0.1Mn1.9O4正极材料,并用X射线衍射光谱法（XRD）、扫描电子显微镜法（SEM）、能量散射光谱（EDS）、充放电测试、CV和EIS对其结构、形貌及电化学性能进行了研究。结果表明,Mg^2＋、Na^＋的掺杂未改变Li Mn2O4的结构。在0.2 C下,样品Li Mn2O4和Li0.95Na0.05Mg0.1Mn1.9O4的首次放电比容量分别为127.1 m Ah/g和123.3 m Ah/g,充放电循环100次后,其容量保持率分别为77.34%和94.81%,Mg2＋、Na＋掺杂后,材料的初始放电比容量略有降低,但循环性能明显得到了改善。在10 C下,Li0.95Na0.05Mg0.1Mn1.9O4的放电比容量高达92.4 m Ah/g。实验表明,Mg2＋、Na＋的共同掺杂有效改善了Li Mn2O4的循环稳定性和倍率性能。

英文摘要：

The lithium-ion battery cathode material LiMn2O4 sufferred from severe capacity fading during the process ofcharge and discharge, and its large-scale application was limited. To overcome this defect, Li0.95Na0.05Mg0.1Mn1.9O4samples was synthesized by solid state reaction route. The effects of Mg^2＋and Na^＋co-doping on the structure,morphology and electrochemical performance of material LiMn2O4 were studied by XRD, SEM, EDS, galvanostaticcharge-dischargeand, CV and EIS, respectively. The results indicate that appropriate amount doping of Mg2＋and Na＋do not change the spinel structure of LiMn2O4. The results reveal that the Li0.95Na0.05Mg0.1Mn1.9O4has an initial dischargecapacity of 123.3 mAh/g at 0.2 C, and the capacity retention is still 94.81% after 100 cycles, although the initialdischarge capacity of Li0.95Na0.05Mg0.1Mn1.9O4 is slightly lower than that of LiMn2O4, the capacity retention ofLi0.95Na0.05Mg0.1Mn1.9O4 is improved significantly. Moreover, the Li0.95Na0.05Mg0.1Mn1.9O4 shows that the discharge capacityis of 92.4 mAh/g at 10 presents an excellent rate capability compared with LiMn2O4. The studies demonstrat thatthe Li0.95Na0.05Mg0.1Mn1.9O4 cathode material has excellent capacity retention and high rate capability.