Influence of silver ion concentration on dielectric characteristics of Li2O-Nb2O5-P2O5 glasses

Abstract

In this work we have studied the dielectric properties of Li 2 O-Nb 2 O 5 -P 2 O 5 : Ag 2 O glasses as a function of Ag 2 O concentration. Auxiliary studies viz., optical absorption, photoluminescence (PL)and IR spectra have also been performed on these glasses. IR spectral studies have indicated that the host glass network doped with 1.0 mol% of Ag 2 O is highly polymerized. Optical absorption and PL studies have clearly exhibited absorption and emission bands due to surface plasmon resonance (SPR). From these studies the presence of Ag 0 -Ag + clusters is established in the glass network and the concentration of such clusters is found to be the highest in the glass doped with 1.0 mol% of Ag 2 O. Finally, we have performed extensive studies on dielectric properties viz., dielectric constant, loss, electric moduli, impedance spectra and a.c. conductivity over broad ranges of frequency (0.01 Hz to 1 MHz) and temperature (303 to 513 K). The glasses doped with higher content of Ag 2 O exhibited higher values of dielectric constant especially at lower frequencies and higher temperatures.The larger contribution from space charge polarization is predicted to be responsible for such higher values. In the glasses doped with low contents of Ag 2 O (< 1.0 mol%) the polaron conductivity (due to the polaronic transfer between Ag 0 and Ag + ions) seemed to be dominant, whereas in the glasses containing more than 1.0 mol% of Ag 2 O, the ionic conduction (due to the diffusion of Ag + and Li + ions) appeared to be prevailed. The impedance diagrams drawn between Z′ and Z″ have further supported the above-mentioned conclusions. From the overall analysis of the results of dielectric properties (including a.c. conductivity ) with the aid of experimental results on spectroscopic studies, it is concluded that the glass containing more than 1.0 mol% of Ag 2 O exhibited predominantly ionic conductivity and hence such glasses may be useful as electrolytes for ionic conducting batteries.

Li2O-ZnO-MoO3-SeO2 glass-nanocomposites and their crystalline counterparts: microstructure, electrical transport mechanism and first principle DFT analysis

“…It is also observed that high amounts of Li + and their small inter-particle contacts are responsible for thermal conductivity up to an extent in this glassy system due to high lattice waves. The Effect of silver ion density may change in the dielectric properties of glassy systems containing Li 2 O [14]. It is also observed from the literature [14] that space charge polarization should act as a major part in changing the values of dielectric constant of Li 2 O-doped glassy systems.…”

“…The Effect of silver ion density may change in the dielectric properties of glassy systems containing Li 2 O [14]. It is also observed from the literature [14] that space charge polarization should act as a major part in changing the values of dielectric constant of Li 2 O-doped glassy systems. Higher Li + doped oxide layered material containing Mg and La-cohave also been found to be promising candidates for exhibiting good electrochemical performance [15].…”

Nióbio: Um Elemento Químico Estratégico Para O Brasil

“…Por exemplo, a taxa de degradação de CaO-Na 2 O-P 2 O 5 pode variar de horas até semanas, dependendo da composição do vidro. Bertran e colaboradores 29 30 Estudos espectrais mostram aglomerados de partículas de prata metálica e íons Ag + nos vidros fabricados. Os vidros dopados com maior teor de Ag 2 O mostraram os maiores valores de constante dielétrica, especialmente em baixas frequências e altas temperaturas.…”

Transport of potassium ions in niobium phosphate glasses

“…Niobium phosphate glasses possess remarkable functional properties which make them attractive for diverse fields of application, from optical and laser technology, 1–6 electrochemical devices 7–13 to nuclear waste immobilization, 14 and biomedicine 15,16 . Generally, the addition of niobium oxide to phosphate glass increases density, glass transition temperature, elastic modulus, refractive index, improves chemical durability, and decreases thermal expansion coefficient 2–4,14,17 …”

“…In combination with alkali oxide, niobium oxide can be incorporated in a phosphate network in a wide compositional range which makes these glass systems interesting from the point of view of electrical properties. Indeed, studies on niobium phosphate glasses containing different alkali oxides, 7–10,13,21 as well as their mixture 12 reveal that structural modifications induced by the incorporation of niobium into phosphate glass have a significant impact on the ionic conductivity. Moreover the study by Graça et al 8 on alkali niobium phosphate glasses shows that while ionic transport takes place above room temperature, at lower temperatures niobium actively contributes to the electrical processes by the electron transfer between niobium ions in different valence states, that is, Nb 5+ and Nb 4+ .…”