An approach to application for LiNi_0.6Co_0.2Mn_0.2O₂ cathode material at high cutoff voltage by TiO₂ coating

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• 作者：Yanping Chen ; Yun Zhang ; ^{y_zhang@scu.edu.cn" class="auth_mail} ; Baojun Chen ; Zongyi Wang ; Chao Lu
• 关键词：Nickel-rich cathode materials ; Electrochemical performance ; Anatase TiO2 coating ; High voltage ; Lithium ion batteries
• 刊名：Journal of Power Sources
• 出版年：15 June, 2014
• 年：2014
• 卷：256
• 期：Complete
• 页码：20-27
• 全文大小：3134 K

文摘

Nickel-rich LiNi_0.6Co_0.2Mn_0.2O₂ 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聽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 LiNi_0.6Co_0.2Mn_0.2O₂ with nanoscale and the coating layer thickness is about 25-35聽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 LiNi_0.6Co_0.2Mn_0.2O₂ presents excellent cycling capability, rate capability and thermal stability at cutoff voltage of 4.5聽V. The 1.0聽wt.% TiO₂-coated LiNi_0.6Co_0.2Mn_0.2O₂ exhibits a capacity retention of 88.7% after 50 cycles at 1聽C and a discharge capacity of 135.8聽mAh聽g^鈭? after 10 cycles at 5聽C, comparing to those of the pristine LiNi_0.6Co_0.2Mn_0.2O₂ of only 78.1% and 85.4聽mAh聽g^鈭?. 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.