Enhancing the High-Voltage Cycling Performance of LiNi0.5Mn0.3Co0.2O2 by Retarding Its Interfacial Reaction with an Electrolyte by Atomic-Layer-Deposited Al2O3

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• 作者：Yantao Su ; Suihan Cui ; Zengqing Zhuo ; Wanli Yang ; Xinwei Wang ; Feng Pan
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：November 18, 2015
• 年：2015
• 卷：7
• 期：45
• 页码：25105-25112
• 全文大小：659K
• ISSN：1944-8252

文摘

High-voltage (>4.3 V) operation of LiNi_xMn_yCo_zO₂ (NMC; 0 鈮?x, y, z < 1) for high capacity has become a new challenge for next-generation lithium-ion batteries because of the rapid capacity degradation over cycling. In this work, we investigate the performance of LiNi_0.5Mn_0.3Co_0.2O₂ (NMC532) electrodes with and without an atomic-layer-deposited (ALD) Al₂O₃ layer for charging/discharging in the range from 3.0 to 4.5 V (high voltage). The results of the electrochemical measurements show that the cells with ALD Al₂O₃-coated NMC532 electrodes have much enhanced cycling stability. The mechanism was investigated by using X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and electrochemical methods. We find that the ultrathin ALD Al₂O₃ film can reduce the interface resistance of lithium-ion diffusion and enhance the surface stability of NMC532 by retarding the reactions at NMC532/electrolyte interfaces for preventing the formation of a new microstructure rock-salt phase NiO around the NMC532 surfaces.