Ag ion conducting glasses

Relaxation behaviour (discussed in chapter 9), of both electrical and mechanical properties, has been studied in phosphate and borate systems. Increased concentration of Agl shifts the mechanical relaxation peaks to lower temperatures at constant frequencies and no new peak was observed which could be associated with a separate population of mobile Ag ions. The relaxed modulus, however, extrapolates to that of the 

Levasseur et al. (1978, 1979) recognized two important factors which influence a. The first was that the replacement of O by S in alkali borate glasses (Li20-B203 to Li2S-B2S3), which increased the room 

Since both Mo and W in the glasses can be reduced to lower valence states 

Therefore the apparent activation energy, = Eg - 14kT. Making 

Systematic transport studies of Li ions in oxide and chalcogenide glasses of the general formula, xLi2X (l-x)SiX2 (X = O, S or Se) by Pradel and Ribes (1994), revealed that conductivities in oxide glasses are significantly low. The d.c. conductivities were found to vary as yfx and this behaviour found support in Monte Carlo computer simulation. Since 

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Figure 6.16, Temperature dependence of conductivity of fast ion conducting glasses. Left Ag ion conducting glasses, right Li ion conducting glasses. Results of some crystalline conductors (c), are shown for comparison (After Minami, 1985)...

A ° Ag NMR study of fast ion conducting glasses in the system Ag2S-B2S3-SiS2 showed 3 well-resolved lines corresponding to 3 Ag species distinguishable both by their chemical environment and their ion dynamics. The NMR data determined as a... 

Table 6.4 Typical examples of fast ion conducting glasses containing Ag or Li ions (After Minami, 1985)...

In the alloy Ag Au, silver is the electronegative component (the less noble one) and gold is the electropositive component (the more noble one). The electrolyte in the given example was a special glass with Ag ion conductivity. The glass was melted on the silver electrode. The electrolyte fihn had a thickness of 0.1 mm and the resistance was of the order of 2000 Q. The cell reaction was described in the previous chapter. The electrode process (Eq. (3.31)) consisted of the transfer of metal atoms from the pure Ag into the alloy environment Agjj AUj, keeping the alloy composition constant. Eqs. (3.33)-(3.37) could then be applied to calculate the partial molar functions of the Ag Au, system. 

Ag NMR in the highly conductive glass was investigated from 230 to 433 K. The ° Ag NMR spectra reveal for the first time three well-resolved lines corresponding to three kinds of chemically speciated Ag ions in sites with different chemical shifts in a macroscopically homogeneous glass. ... 

Structurally these are the wells defined by completely I, completely O or mixed 170 neighborhoods. They give rise to potential wells which are shallow (T), shallow-deep (170 ) and deep (O ). Their connectivities lead to shallow-shallow, shallow-deep and deep-deep combinations. The Ag ions present in wells generated by shallow-shallow interactions contribute most to the conductivity, because their mobilities depend upon connectivity of wells in the glass structure. Thus the well depths and connectivities define both the diffusion path and the mobility. 

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