Study of Structure of Li- and Mn-rich Transition Metal Oxides Using 4D-STEM
Study of Structure of Li- and Mn-rich Transition Metal Oxides Using 4D-STEM
复制标题
使用 4D-STEM 研究富锂和富锰过渡金属氧化物的结构
DOI：
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发表时间：
2016
影响因子：
2.8
通讯作者：
Q. Ramasse
中科院分区：
文献类型：
--
作者：
A. Shukla;C. Ophus;C. Gammer;Q. Ramasse
富锂和富锰过渡金属氧化物（Li1+xM1-xO2，其中M通常是Mn、Co和Ni等过渡金属的组合，以下称为LMRTMO）的结构在过去几年中一直受到广泛争论。最近显示，通过使用高角度环形暗场 (HAADF-) 扫描透射电子显微镜 (STEM) 在多个区域轴上以原子分辨率对整个初级粒子进行成像，大部分氧化物可以描述为由随机堆叠的域组成的非周期性晶体，这些域对应于单斜晶结构的三种变体 [1]，如图 1 (a) 所示。使用 HAADF-STEM 证明，颗粒中不包含如前所述的两相（三角相和单斜相）[2]，因为初级颗粒的尺寸足够小，表明单斜相是整个颗粒中存在的唯一相。然而，为了获得更好的体积能量密度，阴极材料通常优选较大尺寸的颗粒。对于这些应用，以原子分辨率对整个颗粒进行成像非常困难，并且在某些情况下由于区域厚度较高而不可能实现。在本文中，我们演示了 4D-STEM [3] 的使用，在商用阴极材料上使用大视场来确认大部分初级颗粒由单相组成，并由对应于单斜晶相的三种变体的域组成。
The structure of Liand Mn-rich transition metal oxides (Li1+xM1-xO2, where M is usually a combination of transition metals such as Mn, Co and Ni, called LMRTMO henceforth) has been debated extensively for the past several years. It has been recently shown, by imaging entire primary particles at atomic resolution at multiple zone axes using high angle annular dark field (HAADF-) scanning transmission electron microscopy (STEM), that the bulk of the oxides can be described as an aperiodic crystal consisting of randomly stacked domains that correspond to three variants of monoclinic structure [1] as shown in Figure 1 (a). Using HAADF-STEM, it was demonstrated that the particles did not contain two phases (trigonal and monoclinic) in the bulk as described earlier [2], since the size of the primary particles was small enough show that the monoclinic phase was the only phase present in entire particles. However, larger sized particles are often preferred for the cathode materials in order to obtain better volumetric energy density. For these applications, imaging entire particles at atomic resolution is very difficult and in some cases impossible owing to regions of higher thickness. In this paper we demonstrate the use of 4D-STEM [3] using large fields of view on a commercial cathode material to confirm that the bulk of the primary particles is made up of a single phase and consists of domains corresponding to three variants of monoclinic phase.
用于电子晶体学的葡萄糖包埋生物材料的样品平整度受到碳蒸发储备的选择的显着影响。
影响因子：
2.2
作者：
Han,BG;Wolf,SG;Vonck,J;Glaeser,RM
通讯作者：
Glaeser,RM