Li2MnO3复合LiNi0.8Co0.1Mn0.1O2材料制备及电化学性能研究

通过采用共沉淀法制备了Ni0.8Co0.1Mn0.1(OH)2前驱体,利用固相法研磨混合碳酸锰和碳酸锂,在氧气氛围下煅烧制备得到了Li2Mn O3-Li Ni0.8Co0.1Mn0.1O2复合材料,通过利用X射线衍射(XRD)、场发射扫描电镜(FESEM)和透射电镜(TEM)表征了所制备材料的结构、成分和形貌等。通过恒流充放电、交流阻抗等方法对材料的电化学性能进行测试。结果表明,与未改性材料进行对比,3%(质量分数)Li2Mn O3复合改性材料0.5C下首次放电容量为183 m A·h/g,经过120次充放电循环,容量保持率为93.9%;同时,在高倍率下复合改性材料放电容量也得到提高。因此,采用固相法煅烧复合Li2Mn O3-Li Ni0.8Co0.1Mn0.1O2材料,可以制备出电化学性能优异的正极材料。

Study on Synthesis and electrochemical performance of Li2MnO3-LiNi0.8Co0.1Mn0.1O2 composite cathodes materials

A co-precipitation route was utilized to synthesize the precursor of Ni_0.8Co_0.1Mn_0.1（OH）₂,which was mixed with MnCO₃ and Li₂CO₃ afterwards. After calcination in the oxygen atmosphere,Li₂MnO₃-LiNi_0.8Co_0.1Mn_0.1O₂ composite material was obtained.The structure,composition and morphology of the prepared materials were characterized by X-ray diffraction（XRD）,field emission scanning electron microscopy（FESEM） and transmission electron microscopy（TEM）,respectively.The electrochemical performance of the material was tested by galvanostatic charge/discharge measurements and electrochemical impedance spectroscopy.Results showed that the 3%（mass fraction） Li₂MnO₃ composite material exhibit higher initial discharge capability（183 mA·h/g at 0.5C）,more stable cycle performance（with capacity retention of 93.9% after 120 cycles）and better rate performance,compared with unmodified cathode.Thus,this strategy is extremely promising for the preparation of LiNi_0.8Co_0.1Mn_0.1O₂ electrode materials with enhanced electrochemical performances.