Intercalation layered stacking

Figure 5. Structure of LiC6. (a) Left schematic drawing showing the AA layer stacking sequence and the aa interlayer ordering of the intercalated lithium. Right Simplified representation [21. (b) In-plane distribution of Li in LiC6. (c) In-plane distribution of Li in LiC,.

Fig. 9.4 Bright field TEM images of PLA-based nanocomposites prepared with (A) MMT-C1gH3N+, (B) MMT-Clg(CH3)3N+and (C) MMT-2Clg(CH3)2N+. The dark entities are the cross section and/ orfaceofthe intercalated-and-stacked silicate layers and the bright areas are the matrix. Reprinted from [18], 2006, Wiley-VCH.

Ex-situ experiments by Fogg and co-workers suggested that the rhombo-hedral liAl- Cl LDH did not form staging intermediates when reacted with dicarboxylate salts [40]. In-situ measurements have confirmed that these reactions are indeed direct one-step processes. Similarly, staging is not seen for the intercalation of phosfonate salts (Fig. 13a). The alteration of the layer stacking sequence therefore has a profoimd effect on the reaction pathway [41 ]. 

Figure 26. Displacement of the layer stacking sequence (see text) on intercalation of lithium in graphite.11 Reprinted from J. Maier, Physical Chemistry of Ionic Materials. Ions and Electrons in Solids. Copyright 2004 with permission from John Wiley Sons, Ltd.

FIGURE 11.18 Representative TEM images (a) immiscible (b) intercalated with many clay layers stacking together (c) intercalated and uniformly dispersed with a few clay layers stacking together (d) exfoliated (delaminated) with a uniform dispersion. 

Figure 19 Compositions of the alkali metal intercalation com-poimds of TiS2 and ZrS2. (Reprinted with permission from Ref. 4, by permission of Oxford University Press). The numerals refer to the stage, and a, b to different layer stackings (see text)...

Fig. 3 shows the XRD patterns after calcination of as prepared solids at 400 °C in Nz (M-4OO-N2). The disappearance of basal reflections at 20<1O deg suggests the lack of periodicity in the layer stacking. The products for M=Mn, Fe, and Zn exhibited diffraction peaks due to oxides of M, suggesting that part of intercalated metal acetates was precipitated as oxides. The Cu-400-Nz solely produced metallic precipitations in addition to anatase-type TiOz. FT-IR measurement confirmed the complete elimination of the organic components (vch 2840-2960 cm, Vco 1450. 1550 cm ) from these composites. As shown in Table 1, the BET surface areas of M-400-Nz were in the range of 23-100 m /g, compared to 11 m /g for pristine KzTi409 microcrystals. The largest surface area was attained by the Cr-400-Nz... 

Figure 9.12 Transfonnations in electrode materials graphite (part a) changes layer stacking when lithium atoms are intercalated (part b) C0O2 changes from hexagonal closest packing of the oxygen anions to cubic closest packing when lithium atoms are intercalated (part d)...

In conventional polymer composites, the interlayer spacing will remain the same, similar to clay, and there will therefore be no shift of the diffraction peak. But if there is intercalation, the peak position will shift to a lower angle than in the original nanomaterial. The absence of a characteristic diffraction peak is usually the first indication of exfoliation of the nanomaterial, although it is not conclusive. However, several other factors such as a decrease in the degree of coherent layer stacking, very low concentration of nanomaterial and strong absorption by heavy atoms/ions (e.g. bromide) may also affect the accuracy of this analysis. 

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