Electrochemical intercalation kinetics of lithium ions for spinel LiNi_0.5Mn_1.5O₄ cathode material

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• 作者：Ting-Feng Yi ; Chun-Yan Li ; Yan-Rong Zhu ; Rong-Sun Zhu and J. Shu
• 关键词：cathode material ; LiNi0.5Mn1.5O4 ; electrochemical intercalation kinetics ; electrochemical impedance spectroscopy
• 刊名：Russian Journal of Electrochemistry
• 出版时间：February, 2010
• 出版年：2010
• 期刊代码：51_10231935
• 类别：mt
• 卷：46
• 期：2
• 页码：227-232
• 数据来源：sp

摘要

The crystal structure and electrochemical intercalation kinetics of spinel LiNi_0.5Mn_1.5O₄ such as the resistance of a solid electrolyte interphase (SEI) film, charge transfer resistance (R _ct), surface layer capacitance, exchange current density (i ₀), and chemical diffusion coefficient are evaluated by Fourier transform infrared (FT-IR) and electrochemical impedance spectroscopy (EIS), respectively. FT-IR shows that LiNi_0.5Mn_1.5O₄ thus obtained has a cubic spinel structure, which can be indexed in a space group of Fd3m with a disordering distribution of Ni. EIS indicates that R _s is almost a constant at different states of charge. The thickness of SEI film increases with increasing of the cell voltage. R _ct values evidently decreases when lithium ions deintercalated from the cathode in the voltage range from OCV to 4.6 V, and R _ct value increases with increasing potential of deintercalation over 4.7 V. i ₀ varies between 0.2 and 1.6 mA cm−2, and the solid phase diffusion coefficient of Li+ changed depending on the electrode potential in the range of 10−11–10−9 cm2 s−1.