A Versatile Coating Strategy to Highly Improve the Electrochemical Properties of Layered Oxide LiMO2 (M = Ni0.5Mn0.5 and Ni1/3Mn1/3Co1/3)

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• 作者：Enyue Zhao ; Minmin Chen ; Dongfeng Chen ; Xiaoling Xiao ; Zhongbo Hu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：December 16, 2015
• 年：2015
• 卷：7
• 期：49
• 页码：27096-27105
• 全文大小：710K
• ISSN：1944-8252

文摘

This work provides a convenient, effective and highly versatile coating strategy for the layered oxide LiMO₂ (M = Ni_0.5Mn_0.5 and Ni_1/3Mn_1/3Co_1/3). Here, layered oxide LiMO₂ (M = Ni_0.5Mn_0.5 and Ni_1/3Mn_1/3Co_1/3) has been successfully coated with ion conductor of Li₂SiO₃ by in situ hydrolysis of tetraethyl orthosilicate (TEOS) followed by the lithiation process. The discharge capacity, cycle stability, rate capability, and some other electrochemical performances of layered cathode materials LiMO₂ can be highly enhanced through surface-modification by coating appropriate content of Li₂SiO₃. Particularly, the 3 mol % Li₂SiO₃ coated LiNi_1/3Mn_1/3Co_1/3O₂ exhibits approximately a discharge capacity of 111 mAh/g after 300 cycles at the current density of 800 mA/g (5 C). Potentiostatic intermittent titration technique (PITT) test was carried out to investigate the mechanism of the improvement in the electrochemical properties. The diffusion coefficient of Li⁺-ion (D_Li) of Li₂SiO₃ coated layered oxide materials has been greatly increased. We believe our methodology provides a convenient, effective and highly versatile coating strategy, which can be expected to open the way to ameliorate the electrochemical properties of electrode materials for lithium ion batteries.