层状锂离子电池正极材料LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2的制备及性能

Synthesis and Characteristics of Layered LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2 Cathode Material for Lithium Rechargeable Batteries

采用共沉淀法得到前驱体Ni0.8Co0.1Mn0.1(OH)2,利用前驱体与LiOH·H2O的高温固相反应得到高振实密度的锂离子电池层状正极材料LiNi0.8Co0.1Mn0.1O2(2.3～2.5g/cm3).初步探讨了合成条件对材料电化学性能的影响.通过X射线衍射(XRD)、扫描电镜(SEM)、热重-差热分析(TG/DTG)以及恒电流充放电测试对合成的样品进行了测试和表征.结果表明,在750℃、氧气气氛下合成的材料具有较好的电化学性能.通过XRD分析可知该材料为典型的六方晶系α-NaFeO2结构;SEM测试发现产物粒子是由500～800nm的一次小晶粒堆积形成的二次类球形粒子.电化学测试表明,其首次放电容量和库仑效率分别为168.6mA·h/g和90.5%,20次循环后容量为161.7mA·h/g,保持率达到95.9%,是一种具有应用前景的新型锂离子电池正极材料.

Layered LiNi0.8Co0.1Mn0.1O2 powder was synthesized by reacting quasi-spherical Ni0.sCo0.1Mn0.1（OH）2 prepared by co-precipitation with LiOH·H2O through high temperature sintering route. The obtained powder was characterized by X-ray diffraction （XRD）, scanning electronic microscope （SEM）, thermogravimetric-differential thermogravimetric analysis （TG-DTG） and constant current charge-discharge cycling. The results revealed that the optimal preparation condition of the layered LiNi0.8Co0.1Mn0.1O2 was 750 ℃ under oxygen flowing. The XRD pattern of the sample prepared under the above condition could be identified by a typical structure of hexagonal α-NaFeO2 type. The SEM micrograph of LiNi0.8Co0.1Mn0.1O2 showed that a large number of spherical primary particles with an average size of about 500-800 nm piled loosely to form quasi-spherical secondary particles. Electrochemical measurements showed that it delivered an initial discharge capacity of 168.6 mA.h/g during the first charge and discharge cycle, and the first coulombic efficiency was 90.5%, and the discharge capacity in the 20th cycle was 161.7 mA.h/g. The material would be potential cathode material for Li-ion battery.