LiMO₂@Li₂MnO₃ positive-electrode material for high energy density lithium ion batteries

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• 作者：Mohammed Adnan Mezaal ; Limin Qu ; Guanghua Li…
• 关键词：NCM 111 ; Core–shell structure ; Li2MnO3 ; Cathode materials ; Lithium ion battery ; Energy density
• 刊名：Journal of Solid State Electrochemistry
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：21
• 期：1
• 页码：145-152
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Physical Chemistry; Electrochemistry; Energy Storage; Characterization and Evaluation of Materials; Analytical Chemistry; Condensed Matter Physics;
• 出版者：Springer Berlin Heidelberg
• ISSN：1433-0768
• 卷排序：21

文摘

Li[Ni_1/3Co_1/3Mn_1/3]O₂ (NCM 111) is a promising alternative to LiCoO₂, as it is less expensive, more structurally stable, and has better safety characteristics. However, its capacity of 155 mAh g−1 is quite low, and cycling at potentials above 4.5 V leads to rapid capacity deterioration. Here, we report a successful synthesis of lithium-rich layered oxides (LLOs) with a core of LiMO₂ (R-3m, M = Ni, Co) and a shell of Li₂MnO₃ (C2/m) (the molar ratio of Ni, Co to Mn is the same as that in NCM 111). The core–shell structure of these LLOs was confirmed by XRD, TEM, and XPS. The Rietveld refinement data showed that these LLOs possess less Li+/Ni2+ cation disorder and stronger M*–O (M* = Mn, Co, Ni) bonds than NCM 111. The core–shell material Li_1.15Na_0.5(Ni_1/3Co_1/3)_core(Mn_1/3)_shellO₂ can be cycled to a high upper cutoff potential of 4.7 V, delivers a high discharge capacity of 218 mAh g−1 at 20 mA g−1, and retains 90 % of its discharge capacity at 100 mA g−1 after 90 cycles; thus, the use of this material in lithium ion batteries could substantially increase their energy density.