摘要
以Li2CO3,MnCO3和Ni(OH)2为原料,采用一步固相反应制备锂离子电池层状结构正极材料LiNi0.5-Mn0.5O2,采用X射线衍射和扫描电镜对其结构和形貌进行表征,并研究配料时不同初始Li/(Mn+Ni)摩尔比(1.0,1.05,1.1,1.2,1.5)对LiNi0.5Mn0.5O2电化学性能的影响。X射线衍射结果表明,在600℃预烧12 h而后800℃烧结24 h的条件下各样品结晶完整,初始Li/(Mn+Ni)摩尔比为1.5时样品有未知相杂质生成。扫描电镜分析表明,随着初始Li/(Mn+Ni)摩尔比的增大,颗粒团聚加剧。电化学测试结果表明,随着初始Li/(Mn+Ni)摩尔比(≥1.05)的提高,初始容量有下降趋势。初始Li/(Mn+Ni)摩尔比为1.05和1.1时样品首次放电容量分别为167.0 mA.h/g和147.2 mA.h/g,循环20次后容量保持率分别为88.2%和97.8%。
Cathode material LiNi0.5Mn0.5O2 with layered structure was synthesized using Li2CO3, MnCO3 and Ni（OH）2 as starting materials by one-step solid state reaction. The structure and morphology of the synthesized samples were characterized by X-ray diffractrometry and scanning electron microscopy, respectively. And the effect of initial Li/（Mn＋Ni） mole ratio on the electrochemical performance of LiNi0.5Mn0.5O2 was studied. X-ray diffraction results show that the samples synthesized at 600 ℃ for 12 h, followed by calcination at 800 ℃ for 24 h were well crystallized. Some uncertain impurity existed in the sample with initial Li/（Mn＋Ni） mole ratio of 1.5. Scanning electron microscope photographs show that the conglomeration of particles becomes more serious with increasing initial Li/（Mn＋Ni） mole ratio. When initial Li/（Mn＋Ni） mole ratio is equal to or more than 1.05, initial discharge capacity decreases with increasing initial Li/（Mn＋Ni） mole ratio. The first discharge capacities of samples with initial Li/（Mn＋Ni） mole ratio of 1.05 and 1.1 are 167.2 and 147.2 mA·h/g respectively at a specific current of 20 mA/g between 2.5 V and 4.5 V, and retain 88.2% and 97.8% of the initial capacity respectively after 20 cycles.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2006年第8期1434-1438,共5页
The Chinese Journal of Nonferrous Metals
基金
中南大学博士后基金资助项目
