An approach to application for LiNi0.6Co0.2Mn0.2O2 cathode material at high cutoff voltage by TiO2 coating
An approach to application for LiNi0.6Co0.2Mn0.2O2 cathode material at high cutoff voltage by TiO2 coating
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DOI：
10.1016/j.jpowsour.2014.01.061
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发表时间：
2014-06-15
影响因子：
9.2
通讯作者：
Lu, Chao
中科院分区：
文献类型：
--
作者：
Chen, Yanping;Zhang, Yun;Lu, Chao
采用水解法合成纳米TiO 2包覆富镍LiNi0.6Co0.2Mn0.2O2正极材料，以提高其在4.5V高截止电压下的电化学性能。透射电子显微镜（TEM）和高分辨透射电子显微镜（HRTEM）结果表明，在LiNi0.6Co0.2Mn0.2O2表面成功包覆了纳米级的TiO 2，包覆层厚度约为25-35 nm。X射线衍射（XRD）测试结果表明，适量的TiO 2包覆有利于形成良好的层状结构，且阳离子无序度较小。充放电测试结果表明，TiO 2包覆的LiNi0.6Co0.2Mn0.2O2在4.5V的截止电压下具有优异的循环性能、倍率性能和热稳定性。TiO 2包覆的LiNi0.6Co0.2Mn0.2O2在1C下循环50次后的容量保持率为88.7%，在5C下循环10次后的放电容量为135.8mAh g（-1），而未包覆的LiNi0.6Co0.2Mn0.2O2在1C下循环50次后的容量保持率为78.1%，在5C下循环10次后的放电容量为85.4mAh g（-1）。电化学阻抗谱（EIS）和差示扫描量热仪（DSC）测试结果表明，涂层抑制了阴极与电解质之间的界面反应，提高了材料的结构稳定性，从而改善了材料的电化学性能。(C)2014爱思唯尔有限公司版权所有。
Nickel-rich LiNi0.6Co0.2Mn0.2O2 cathode material is coated with nano-sized anatase TiO2 synthesized via hydrolyzation method to improve its electrochemical performance at high cutoff voltage of 4.5 V. Scanning electron microscopy (SEM), transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) results show that the anatase TiO2 is successfully coated on the surface of LiNi0.6Co0.2Mn0.2O2 with nanoscale and the coating layer thickness is about 25-35 nm. X-ray diffraction (XRD) test results indicate that appropriate amount of TiO2 coating is beneficial to form a good layered structure with less cation disorder. Charge-discharge test results demonstrate that the TiO2-coated LiNi0.6Co0.2Mn0.2O2 presents excellent cycling capability, rate capability and thermal stability at cutoff voltage of 4.5 V. The 1.0 wt.% TiO2-coated LiNi0.6Co0.2Mn0.2O2 exhibits a capacity retention of 88.7% after 50 cycles at 1 C and a discharge capacity of 135.8 mAh g(-1) after 10 cycles at 5 C, comparing to those of the pristine LiNi0.6Co0.2Mn0.2O2 of only 78.1% and 85.4 mAh g(-1). Electrochemical impedance spectroscopy (EIS) and differential scanning calorimeter (DSC) tests results provide evidence that the improved electrochemical properties are mainly attributed to the suppression of the interface reaction between the cathode and electrolyte and the improvement of structural stability of the material by coating. (C) 2014 Elsevier B.V. All rights reserved.