Synthesis of Li[(Ni0.5Mn0.5)1-xLix]O2 by Emulsion Drying Method and Impact of Excess Li on Structural and Electrochemical Properties
Synthesis of Li[(Ni0.5Mn0.5)1-xLix]O2 by Emulsion Drying Method and Impact of Excess Li on Structural and Electrochemical Properties
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DOI：
10.1021/cm052704j
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发表时间：
2006-02
影响因子：
8.6
通讯作者：
Seung‐Taek Myung;S. Komaba;Koutarou Kurihara;Kiyoharu Hosoya;N. Kumagai;Yang‐Kook Sun;I. Nakai;
中科院分区：
文献类型：
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作者：
Seung‐Taek Myung;S. Komaba;Koutarou Kurihara;Kiyoharu Hosoya;N. Kumagai;Yang‐Kook Sun;I. Nakai;
采用乳液干燥法合成了Li[Ni 0. 5 Mn 0. 5]O2（R3 m空间群）层状结构，并研究了Li对过渡金属层的影响。通过X射线衍射、中子衍射和X射线吸收近边光谱对最终产物进行了结构分析。从结构研究中，我们发现，过量的Li位于过渡金属层，过渡金属中Li的存在显着改善了晶体结构中的结构有序性。相对于Li[Ni0.5Mn0.5]O2，Li过量Li[（Ni0.5Mn0.5）0.94Li0.06]O2化合物实现了具有良好循环性的高容量、更快的Li+化学扩散率、由Li+脱/嵌入引起的主体结构的较少变化以及更高的热稳定性。据信，这种增强的电化学性能与Li过量的Li[（Ni0.5Mn0.5）0.94Li0.06]O2的改进的物理和结构性能有关。
Layered Li[Ni0.5Mn0.5]O2 (R3m space group) was synthesized with controlling the Li/(Ni + Mn) ratio by employing an emulsion drying method, and the effect of Li on the transition-metal layer was investigated. Structural analyses of the final products were done by X-ray diffraction, neutron diffraction, and X-ray absorption near-edge spectroscopy. From the structural studies, we found that an excess amount of Li is located at the transition-metal layer and the presence of Li in the transition metal significantly improved structural ordering in the crystal structure. High capacity with good cyclability, faster Li+ chemical diffusivity, less changes in the host structure by Li+ de-/intercalation, and higher thermal stability were achieved for the Li-excess Li[(Ni0.5Mn0.5)0.94Li0.06]O2 compound relative to Li[Ni0.5Mn0.5]O2. It is believed that such enhanced electrochemical properties are related to the improved physical and structural properties of Li-excess Li[(Ni0.5Mn0.5)0.94Li0.06]O2.