摘要
为提高尖晶石LiMn2O4正极材料的电化学性能,通过沉淀法对尖晶石LiMn2O4样品进行氟化钙表面包覆处理,并研究表面包覆对材料的微观结构、形貌及电化学性能的影响。采用X射线衍射(XRD)、扫描电镜(SEM)及电子衍射能谱(EDS)等分析方法对目标材料的形貌进行表征,通过循环充放电测试、循环伏安法等方法研究其电化学性能。XRD结果表明微量的包覆对材料的结构没有明显影响;SEM与EDS表明CaF2以纳米颗粒的形态包覆在样品颗粒表面;电化学测试表明:包覆样品虽初始放电容量下降,但包覆CaF2后的样品较未包覆样品具有更好的循环性能与倍率性能,在55℃充放电倍率为1 C的情况下,包覆质量分数2%的样品较未包覆样品经过20次循环后容量保持率提高了4.3%。
In order to improve the electrochemical performance of spinel LiMn204, spinel LiMn204 was coated with CaF2 by precipitation method, and the effect of surface coating on structure, morphology and electrochemical properties of materials were studied. The related samples were characterized using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and electron diffraction spectrum （EDS） analysis. The electrochemical performance was tested by cyclic voltammetry and cycling experiment. XRD results reveal that the coating does not affect the crystal structure of LiMn204. XRD results reveal that the coating does not affect the crystal structure of LiMn204.The SEM image and EDS show that the surface of the samples are successfully coated with CaF2in the form of nano-particles. Compared to the uncoated LiMn204, electrochemical tests show that in spite of the capacity of coated samples are degressive, but the cycle performance and rate capability are improved. At 55 C, with 1 C rate after circulated 20 times, the capacity retention rate of coated 2% samples compare to the uncoated samples is increased 4.3%
出处
《电源技术》
CAS
CSCD
北大核心
2013年第11期1925-1928,共4页
Chinese Journal of Power Sources
基金
电力与交通材料保护湖南省重点实验室开放基金资助(2011CL04)
关键词
尖晶石LIMN2O4
沉淀法
电化学性能
循环性能
包覆
spinel LiMn2O4
precipitation method
electrochemical properties
cycle performance
coated
