Controlling Solid-Electrolyte-Interphase Layer by Coating P-Type Semiconductor NiOx on Li4Ti5O12 for High-Energy-Density Lithium-Ion Batteries

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• 作者：Mi Ru Jo ; Gi-Hyeok Lee ; Yong-Mook Kang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：December 23, 2015
• 年：2015
• 卷：7
• 期：50
• 页码：27934-27939
• 全文大小：460K
• ISSN：1944-8252

文摘

Li₄Ti₅O₁₂ is a promising anode material for rechargeable lithium batteries due to its well-known zero strain and superb kinetic properties. However, Li₄Ti₅O₁₂ shows low energy density above 1 V vs Li⁺/Li. In order to improve the energy density of Li₄Ti₅O₁₂, its low-voltage intercalation behavior beyond Li₇Ti₅O₁₂ has been demonstrated. In this approach, the extended voltage window is accompanied by the decomposition of liquid electrolyte below 1 V, which would lead to an excessive formation of solid electrolyte interphase (SEI) films. We demonstrate an effective method to improve electrochemical performance of Li₄Ti₅O₁₂ in a wide working voltage range by coating Li₄Ti₅O₁₂ powder with p-type semiconductor NiO_x. Ex situ XRD, XPS, and FTIR results show that the NiO_x coating suppresses electrochemical reduction reactions of the organic SEI components to Li₂CO₃, thereby promoting reversibility of the charge/discharge process. The NiO_x coating layer offers a stable SEI film for enhanced rate capability and cyclability.