Electron microporous material

Key words microporous materials, zeolites, electron microscopy, structure determination... 

The use of the latest experimental analysis and detection techniques including liquid/ solid NMR, XRD, electron diffraction, and in situ analysis is very necessary for the studies on the roles of the SDAs in the crystallization process of microporous materials, which could help us gain a better understanding of the formation mechanism of the pore systems and reveal the real correlation between guest molecules or ions and the resultant frameworks. 

It is well known that experimental CVs for species in solution phase frequently diverge from theoretical ones for -electron reversible couples. The divergence can be caused by a variety of factors deviations from reversibility, occurrence of coupled chemical reactions and/or surface effects, and resistive and capacitive effects (Nicholson and Shain, 1964 Nicholson, 1965a). These last effects will be briefly treated here because of their potential significance when microheterogenous deposits or more or less homogeneous coatings of microporous materials cover the electrode surface. 

Then, the progress of the reaction across the microporous material involves a series of electron exchange plus ion exchange reactions between immobile redox centers, which can be represented via ... 

In the above equation, D, Dy, D, represent the charge diffusion coefficients along the X, y, and z directions. This formulation assumes that both electrons and ions are exchanged simultaneously and that no charge separation effects occur. The above diffusion coefficients will depend, in general, on the orientation of the particles of microporous material. 

Gel batteries require an additional separator to fix the plate distance and to prevent electronic shorts. The most effective protection against shorts is achieved by means of separators with low pore size ideally, microporous materials should be used (pore size less than 1 pm). Additionally, the separator should have a low acid-displacement since the fumed silica and the cracks in the gel already reduce the volume available for electrolyte. To minimize the internal resistance of the battery, the electrical resistance of the separator should be as low as possible. These two requirements, viz., low acid-displacement and low electrical resistance, translate into a need for separators with good wettability, high porosity, and low geometrical volume, i.e., rib configuration and backweb thickness should both be optimized. 

Inorganic porous materials have been quickly developed during the past half century, and have found wide applications in fields such as catalytic, adsorbent, electronic, and environmental technologies. Porous materials are classified into microporous, mesoporous, and macroporous materials according to their pore size. Microporous materials have pore diameters below 2nm, and macroporous materials have pore diameter greater than 50 nm, with mesoporous materials lying in between [1] (Figure 8.1). 

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