Molten salt synthesis and electrochemical properties of LiNi_1/3Co_1/3Mn_1/3O₂ cathode materials

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• 作者：Huali Zhu ; Jie Li ; Zhaoyong Chen ; Qifeng Li ; Tian Xie ; Lingjun Li ; Yanqing Lai
• 关键词：LiNi1/3Co1/3Mn1/3O2 ; Molten salt synthesis ; Cathode materials ; Lithium ion batteries
• 刊名：Synthetic Metals
• 出版年：January, 2014
• 年：2014
• 卷：187
• 期：Complete
• 页码：123-129
• 全文大小：2221 K

文摘

LiNi_1/3Co_1/3Mn_1/3O₂ cathode materials were synthesized by molten salt method. The preparation was performed by sintering the mixture of Ni_1/3Co_1/3Mn_1/3(OH) ₂ and the eutectic molten salts 0.76LiOH路H₂O-0.24Li₂CO₃ at 750-900 掳C for 2-11 h. The prepared particles were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge test. XRD analysis shows the molten salt method can enhance the ordering degree of the layered structure and reduce the cation mixing of LiNi_1/3Co_1/3Mn_1/3O₂ compounds. The sample prepared at 850 掳C for 5 h exhibits an excellent electrochemical performance. It can deliver an initial discharge capacity of 175.6 mAh g^鈭? at a current density of 16 mA g^鈭? between 2.8 and 4.4 V, and a capacity of 156.7 mAh g^鈭? is retained after 2, 10, 20 and 20 cycles at the corresponding current density of 16 mA g^鈭?, 32 mA g^鈭?, 80 mA g^鈭? and 160 mA g^鈭?, respectively. At a current density of 320 mA g^鈭? followingly, it still exhibits a capacity of 150.5 mAh g^鈭? after 20 cycles. The electrochemical impedance shows the charge-discharge process of electrode is controlled by the lithium ion diffusion. It is concluded that the molten salt synthesis can substantially reduce the calcination temperature and shorten the soaking time.