球形正极材料LiNi_(0.75)Co_(0.2)Mg_(0.05)O_2的合成及表征  

Synthesis and characterization of spherical LiNi_(0.75)Co_(0.2)Mg_(0.05)O_2 cathode materials

作　　者：刘艳君[1] 胡国荣[1] 高绪光[1] 彭忠东[1] 

机构地区：[1]中南大学冶金科学与工程学院,湖南长沙410083

出　　处：《电源技术》2007年第7期523-525,529,共4页Chinese Journal of Power Sources

摘　　要：用控制结晶法合成球形材料Ni0.75Co0.2Mg0.05(OH)2与LiOH·H2O混合后,在750℃氧气气氛中焙烧得到LiNi0.75-Co0.2Mg0.05O2。电镜扫描(SEM)结果显示,焙烧后的材料保持了原有的球形形貌。X射线衍射光谱(XRD)和能量色散谱显微分析(EDS)显示,掺镁后的样品晶型结构好,所得产物成分均一。电化学测试表明,LiNi075Co0.2Mg0.05O2材料表现出优良的电化学性能,其首次充电比容量达到271mAh/g,首次放电比容量达到217.7mAh/g,循环50次后放电比容量仍能保持211.7mAh/g,仅衰减了3%(3.0～4.3V,0.2C)。结果表明,镁的掺入减少了材料的阳离子混排,大大提高了循环性能,抑制了充放电过程中的相变和电池阻抗的增加。LiNi0.75Co0.2Mg0.05O2 was synthesized by heat-treating the results mixture of Ni0.75Co0.2Mg0.05（OH）2and LiOH·H2O at 750 ℃ in flowing O2 for 12 h.The SEM results indicate that the active cathode materials maintain the spherical morphology. The crystal structure and element distribution of Ni, Co, Mg on the atomic scale in LiNi0.75Co0.2Mg0.05O2 were analyzed by X-ray diffration and energy dispersive spectrometer （EDS）.The charge-discharge cell displayed excellent electrochemical performances. The first charge capacity and discharge capacity were 271 mAh/g and 217.7 mAh/g, respectively. After 50 cycles, the discharge capacity retained at 211.7 mAh/g, the discharge capacity only lose 3% （3.0-4.3 V, 0.2 C）,which attribute to the doping Mg decreasing the ＂cation disorder＂ and stabilizing the structure during the charge-discharge process.

关 键 词：锂离子蓄电池 LiNi0.75Co0.2Mg0.05O2 正极材料 

分 类 号：TM912.9[电气工程—电力电子与电力传动]