摘要
采用溶胶-凝胶法合成了掺杂改性的锂离子电池正极材料LiCo0.7Al0.3O2,并对其进行包覆MgO改性。采用X射线衍射和扫描电镜对该材料的晶体结构和表观形貌进行分析,通过恒电流充放电、循环伏安以及电化学阻抗技术分析其电化学性能。试验结果表明,所制备的正极材料LiCo0.7Al0.3O2和MgO-LiCo0.7Al0.3O2均为α-NaFeO2型层状结构,形貌近似球形,且颗粒分布均匀。包覆后的材料充放电电压提高,充放电循环性能得到明显改善,其中以包覆量为1.0%时材料性能最好,首次放电容量为120.17 mAh.g?1,30次循环后容量保持率为89.3%。
LiCo0.7Al0.3O2 cathode materials of lithium-ion baterry were synthesized by sol-gel method, then its surface was coated with a thin layer of MgO. The LiCo0.7Al0.3O2 and MgO coated LiCo0.7Al0.3O2 powders were characterized by means of X-ray diffraction（XRD）and scanning electron microscopy（SEM）. The electrochemical properties of the LiCo0.7Al0.3O2 and MgO coated LiCo0.7Al0.3O2 were examined by galvanostatic charge-discharge tests, cyclic voltammogram and electrochemical impedance spectroscopy（EIS）. The result shows that both the LiCo0.7Al0.3O2 and MgO coated LiCo0.7Al0.3O2 particles possess a spherical morphology and uniform particle size with the α-NaFeO2 layer structure.The voltage of charge-discharge was increased after coating. And also the cyclic properties for charge-discharge was improved evidently. Among others the best electrochemical performance is gotten when the coating amount of MgO is 1.0% which could export 117.6 mA·h·g^-1 of the discharge special capacity at initial cycle and remain 91.1% of the initial capacity after 30 cycles.
出处
《粉末冶金材料科学与工程》
EI
2007年第2期112-116,共5页
Materials Science and Engineering of Powder Metallurgy
