高倍率型微米级单晶锂离子电池正极材料

Single crystal and micro-size LiMn_2O_4 cathode material for lithium ion batteries

主要研究了具有微米级单晶改性正极材料LiMn1.82Al0.18O4的基本物理和电化学性能,并考察了该材料在18650型高功率锂离子电池中的应用。通过扫描电子显微镜法(SEM)照片可看出该材料由平均粒径为6～8μm的具有八面体单晶颗粒组成,比表面积小于0.4m2/g,振实密度可达2.4g/cm3。电化学性能测试表明,样品LiMn1.82Al0.18O4在3.0～4.35V(vs.Li/Li+)充放电电压范围内,可逆比容量可达100mAh/g。以该材料为正极材料的18650型高功率锂离子电池容量可达1000mAh,30C倍率放电容量保持率达到0.2C倍率下的92%以上,具有优异的倍率性能。

The physical and chemical performance of single crystal and micro-size modified LiMn1.82Al0.18O4 was researched and the application of 18650 high-power lithium-ion batteries was evaluated.The SEM images show that the sample is composed of the well-defined polyhedron crystalline particles with the average particle diameter of 6-8 μm,the specific surface area is samller than 0.4 m2/g,and the tap density can reach 2.4 g/cm^3.Electrochemical performance test shows that spinel-structured LiMn1.82Al0.18O4 has an initial discharge capacity of 100 mAh/g in the voltage ranges of 3.0-4.35 V （vs Li/Li＋）.The 18650-size high power lithium ion battery based on Mn-spinel as the cathode material has the capacity of 1 000 mAh with excellent rate capability and the discharge capacity retention at 30 C can reach over 92% of that at 0.2 C.