高容量锂离子电池正极材料LiNi0.9Co0.05Mn0.025Mg0.025O2的合成及电化学性能
Synthesis and Electrochemical Properties of High Capacity LiNi0.9Co0.05Mn0.025Mg0.025O2 Cathode for Lithium Ion Batteries
作者单位
胡国荣 中南大学冶金科学与工程学院长沙 410083 
刘 强 中南大学冶金科学与工程学院长沙 410083 
杜 柯 中南大学冶金科学与工程学院长沙 410083 
彭忠东 中南大学冶金科学与工程学院长沙 410083 
曹雁冰 中南大学冶金科学与工程学院长沙 410083 
刘万民 中南大学冶金科学与工程学院长沙 410083 
摘要: 以β-Ni0.9Co0.05Mn0.025Mg0.025(OH)2和LiOH·H2O为原料通过高温固相法合成了球形LiNi0.9Co0.05Mn0.025Mg0.025O2。采用热重-差热分析了反应过程,采用X射线衍射和扫描电镜对粉末的结构和形貌进行了表征。采用充放电测试和循环伏安测试对材料电化学性能进行了研究。结果表明:750 ℃煅烧12 h合成的LiNi0.9Co0.05Mn0.025Mg0.025O2为Li原子混排较少的良好层状结构,二次颗粒尺寸在15 μm左右,且具有最高的放电比容量和良好的循环性能,在0.2C,2.8~4.3 V的条件下,首次放电比容量达207 mAh· g-1,40次循环后容量保持率为92.5%。
关键词: 锂离子电池  正极材料  LiNi0.9Co0.05Mn0.025Mg0.025O2  高容量
基金项目: 
Abstract: Layered structured LiNi0.9Co0.05Mn0.025Mg0.025O2 was successfully synthesized by heating a mixture of β-Ni0.9Co0.05Mn0.025Mg0.025(OH)2 and LiOH·H2O at elevated temperature. Differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA) were employed to study the reaction process. The Ni0.9Co0.05Mn0.025Mg0.025(OH)2 and synthesized LiNi0.9Co0.05Mn0.025Mg0.025O2 were characterized by means of X-ray diffraction (XRD) and scanning electron microscope (SEM), while the electrochemical properties of LiNi0.9Co0.05Mn0.025Mg0.025O2 were investigated by charge-discharge test and cyclic voltammetry (CV). Structure analysis shows the LiNi0.9Co0.05Mn0.025Mg0.025O2 synthsized at 750 ℃ for 12 h possess a well-layered hexagonal structure and a low level of the cation-mixing of Li layer. Scaning electron micrographs reveal that the morphology of the samples is characterized by spherical second particles of ~15 μm. The analysis from electrochemical test suggests that heating the mixture at 750 ℃ for 12 h is the optimized synthesis condition for highest initial discharge capacity and best cycling performance. The first discharge specific capacity between 2.8 and 4.3 V at 0.2C is tested to be 207 mAh·g-1 and 92.5% of the discharge capacity remained after 40 cycles.The CV result shows that the multi-doping of Co, Mn and Mg has strengthened the cycling capability.
Keywords: lithium ion batteries  cathode  LiNi0.9Co0.05Mn0.025Mg0.025O2  high capacity
 
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胡国荣,刘 强,杜 柯,彭忠东,曹雁冰,刘万民.高容量锂离子电池正极材料LiNi0.9Co0.05Mn0.025Mg0.025O2的合成及电化学性能[J].无机化学学报,2012,28(6):1171-1176.
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