高倍率性能锂离子电池LiNi1/3Co1/3Mn1/3O2正极材料的制备及其电化学性能

摘要

A spherical Li[Ni1/3Co1/3Mn1/3]O2 cathode material for lithium-ion batteries was synthesized using a combination of modified carbonate co-precipitation and solid-state methods. The as-prepared material was analyzed using X-ray diffractometry (XRD), scanning electron microscopy (SEM), galvanostatic charge-discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The results indicate that the material synthesized using this new method has a wel-ordered layered structure,α-NaFeO2 [space group:R3m (166)], a spherical morphology, and an average particle size of 157 nm. Electrochemical measurements showed that the material has a good rate capability and long-term cycling performance. At a current density of 0.1C (1.0C=180 mA∙g-1) in the voltage range 2.7-4.3 V, the initial discharge capacity was 156.4 mAh∙g-1 and the coulombic efficiency was 81.9%. At 0.5C, 5C, and 20C, the specific capacities of the material were 136.9, 111.3, and 81.3 mAh∙g-1, respectively. After 100 cycles at 1C, the material retained 92.9%of its initial capacity;this is higher than those of materials prepared using conventional carbonate co-precipitation (87.0%).%采用改进的碳酸盐共沉淀与高温固相法相结合的方法制备出了高倍率性能的锂离子电池正极材料Li[Ni1/3Co1/3Mn1/3]O2,通过X射线衍射(XRD)、扫描电镜(SEM)、循环伏安扫描(CV)、电化学阻抗谱(EIS)和电化学性能测试等手段对材料进行表征.结果表明,该方法制备的材料具有良好的α-NaFeO2型层状结构(R3m (166)),一次粒径平均大小为157 nm,二次颗粒成球形.同传统碳酸盐制备得到的材料相比,该材料具备良好的倍率性能和循环性能,在2.7-4.3 V电压范围内,0.1C (1.0C=180 mA∙g-1)倍率下,首次放电比容量为156.4 mAh∙g-1,库仑效率为81.9%.在较高倍率下,即0.5C、5.0C和20C时,其放电比容量分别为136.9、111.3、81.3 mAh∙g-1.在1C倍率下100次循环容量保持率为92.9%,高于传统共沉淀法得到的材料(87.0%).