Mesoscopic structure features in synthetic graphite
Mesoscopic structure features in synthetic graphite
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DOI：
10.1016/j.matdes.2018.01.038
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发表时间：
2018-03-15
影响因子：
8.4
通讯作者：
Wu, Houzheng
中科院分区：
文献类型：
--
作者：
Marz, Benjamin;Jolley, Kenny;Wu, Houzheng
用高分辨透射电子显微镜（TEM）和拉曼光谱研究了合成石墨级焦炭填料和粘结碳区的介观结构特征。在填料中，三维结构由具有数百纳米的基面尺寸（L-a）和数十纳米的厚度（L-c）的晶体薄片组成。这些薄片具有几乎完美的石墨结构，具有几乎平行的c轴，但它们的a-b平面随机取向，形成“疯狂铺路”结构。在结合碳区域中存在类似的结构，具有较小的L-a。喹啉不溶包裹体及其周围石墨区普遍存在明显的弯曲纹层。通过TEM测量的L-a值与从这些区域中的D与G拉曼峰的强度比估计的一致。原子模型发现，疯狂铺路结构中的最低能量界面包括5、6和7元碳环。弯曲的薄片倾向于保持6个成员环，但弹性应变。我们认为，一个7元碳环离开一个代表扶手椅石墨边缘贡献的拉曼光谱D峰的空腔。(c)2018由Elsevier Ltd.出版
The mesocopic structure features in the coke fillers and binding carbon regions of a synthetic graphite grade have been examined by high resolution transmission electron microscopy (TEM) and Raman spectroscopy. Within the fillers, the three-dimensional structure is composed of crystal laminae with the basal plane dimensions (L-a) of hundreds nanometres, and thicknesses (L-c) of tens of nanometres These laminae have a nearly perfect graphite structure with almost parallel c-axes, but their a-b planes are orientated randomly to form a "crazy paving" structure. A similar structure exists in the binding carbon regions, with a smaller L-a. Significantly bent laminae are widely seen in quinoline insoluble inclusions and the graphite regions developed around them. The L-a values measured by TEM are consistent with estimates from the intensity ratios of the D to G Raman peak in these regions. Atomistic modelling finds that the lowest energy interfaces in the crazy paving structure comprise 5, 6 and 7 member carbon rings. The bent laminae tend to maintain the 6 member rings, but are strained elastically. We suggest that a 7 member carbon ring leaves a cavity representing an arm-chair graphite edge contributing to the Raman spectra D peak. (c) 2018 Published by Elsevier Ltd.