Superionic conductivity

Lindan PJD, Gillan MJ (1993) Shell-model molecular-dynamics simulation of superionic conduction in CAF2. J Phys Conden Matter 5(8) 1019—1030... 

Superionic conducting glass systems, 12 586 Superior vena cava, 5 80 Super iron cells, 3 431t Superlattice(s), 13 499, 19 166 via MOCVD, 22 158-160 Superleaks, 17 354 Super Lewis acids, 12 191 Superluminscent LEDs, 22 176 Supermilling acid dyes, 26 396 Super milling dyes, 9 184, 185 Super-moire pattern, 17 428 Supermolecular organization, of polyamide fibers, 19 740... 

The calculated diffusion constants of hydrogen and oxygen atoms are shown in Figure 9. The inset plot shows the equation of state for this isotherm for both L and S simulations. The two results are virtually identical up until 2.6 g/cc. At 34 GPa (2.0 gIcc), the hydrogen atom diffusion constant has achieved values associated with superionic conductivity (greater than... 

A word about the so-called normal-superionic conducting state transitions would be in order. It seems to be wrong to refer to these transitions as superionic transitions by analogy with the electronic superconducting transitions. While Agl related materials show a marked jump in ionic conductivity at a transition temperature, there are many other superionic materials that do not.60... 

As described in the previous section, the smaller change of the TBOP of Li ion with the movement through the conduction path was observed in the Li3N crystal. In this section, we have tried to estimate the relationship between the ionic conductivity and chemical bonding of the moving Li ions in the sulfide-based superionic conducting glasses. 

Molecular Dynamics Simulation of Superionic Conduction in Cap2. 

Kawamura, J. and Shimoji, M. Ionic conductivity and glass transition in superionic conducting glasses II. Structural relaxation and excess free volume theory. J. Non-Cryst. Solids 88 295, 1986. 

Fu, J., Superionic conductivity of glass-ceramics in the system Li20-Al20j-Ti02-PjOj, Solid State Ionics, 96, 195, 1997. 

The data in Table 1 also illustrate several additional facets of solid state ionic conduction. First the fast (or super ) ion conductors are charaeterized by very low activation energies for conduction (12-36 kj/mol) compared to the normal ionic conductors (> 60 kJ/mol). The low activation energy for superionic conduction is a major contributing factor to the high ionic conductivity at relatively low temperatures. 

I. An Example of Superionic Conductivity The NH4I03 2NHI03 Crystal... 

Thus, the polaronic mechanism of the superionic conductivity in the crystal of ammonium triiodate, which we propose in this chapter, is yet another, novel conception in the range of the known [149,150,203,204] modernized models of the hopping and continuous diffusion. 

H.R. Leuchtag and V.S. Bystrov, Theoretical models of coifformational transitions and ion conduction in voltage-dependent ion channels Bioferroelec-tricity and superionic conduction, Ferroelectrics 220(1), 157-204, (1999). doi 10.1080/00150199908216214... 

There are numerous publications concerning the theory and applications of superionic conduction(see also the Preface). Table 3.1 gives the main electrical parameters of some typical superionic conductors. Superionic conductivity has been observed for a number of ions, Ag", Li+, Na+, K+, Cu+, Pb +, F", O ", NH4+, H+(H20) the lowest , has been found in Agl-based materials. Some compounds exhibit both high ionic and electronic conductivity. Glassy materials are usually poorer conductors and have higher activation energy than crystalline materials of similar composition. 

In good conductors, the diffusion coefficient can attain a value similar to that in aqueous solution or in the molten state ( 10 cm s" ). The corresponding value of the ionic mobility is about 10 cm /Vs. This has been observed for many non-protonic conductors (the main examples are given in Table 4.1) and for some protonic materials (Table 4.2). If the number of mobile ions is suflSciently high, superionic conductivity occurs. ... 

Ph. Colomban and A. Novak, Proton transfer and superionic conductivity in solids and gels, J. Mol. Struct. Ill (1988) 277-308. 

Modelling of superionic conduction has received relatively little attention. Experimental studies, concerned mainly with the measurements of... 

Progress in the understanding of superionic conduction is due to the use of various advanced techniques (X-ray (neutron) diffuse scattering, Raman spectroscopy and a.c.-impedance spectroscopy) and-in the particular case of protons - neutron scattering, nuclear magnetic resonance, infrared spectroscopy and microwave dielectric relaxation appear to be the most powerful methods. A number of books about solid electrolytes published since 1976 hardly mention proton conductors and relatively few review papers, limited in scope, have appeared on this subject. Proton transfer across biological membranes has received considerable attention but is not considered here (see references for more details). 

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