Insight into the Atomic Structure of Cycled Lithium-Rich Layered Oxide Li1.20Mn0.54Co0.13Ni0.13O2 Using HAADF STEM and Electron Nanodiffraction
Insight into the Atomic Structure of Cycled Lithium-Rich Layered Oxide Li1.20Mn0.54Co0.13Ni0.13O2 Using HAADF STEM and Electron Nanodiffraction
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DOI：
10.1021/jp509388j
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发表时间：
2015-01-08
影响因子：
3.7
通讯作者：
Weill, Francois
中科院分区：
文献类型：
--
作者：
Genevois, Cecile;Koga, Hideyuki;Weill, Francois
用像差校正的高角度环形暗场扫描电子显微镜(HAADF STEM)和电子纳米衍射研究了在不同条件下单次充放电循环后回收的三种富锂层状氧化物的局域原子结构的变化。对原始材料Li1.20Mn0.54Co0.13Ni0.13O2的结构进行了全面的表征。然后将其与锂电池一次电化学循环后回收的材料的电压上限进行比较，上限电压要么略低于富锂层状氧化物典型的不可逆平台电压，要么略高于后者。对化学方法得到的材料进行了深入的研究，经过氧化脱嵌锂，然后还原再嵌锂，作为比较。这篇论文的主要信息是，平台期与材料的广泛结构重组无关。与阳离子迁移相关的不可逆过程仅限于颗粒的外部。这里报道的结果支持氧离子的氧化，我们先前提出的可逆氧化发生在粒子的核心，并被认为是富锂和富锰层状氧化物非凡容量的实际来源。
Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF STEM) and electron nanodiffraction investigations have been carried out to follow changes in the local atomic structure of three Li-rich layered oxides recovered after a single chargedischarge cycle, performed in different conditions. The structure of the pristine material Li1.20Mn0.54Co0.13Ni0.13O2 was fully characterized. It was then compared to those of the materials recovered after one electrochemical cycle in a lithium battery, with the upper voltage limit being either just below the voltage of the irreversible plateau typical of Li-rich layered oxides or just above. An in-depth study of the material obtained chemically, after oxidation to deintercalate Li and then reduction to reintercalate Li, was also performed for comparison. The main message of this paper is that the plateau is not associated with an extended structural reorganization of the material. The irreversible processes associated with cation migration are restricted to the external part of the particles. The results reported here support the oxidation of oxygen ions we earlier proposed to occur reversibly in the core of the particles and to be the actual origin for the exceptional capacity of Li- and Mn-rich layered oxides.