A model for the fast ionic diffusion in alumina-doped LiI

Ion transport behavior in a new fast Ag+ ion conducting composite electrolyte system: 0.85[0.75AgI:0.25AgCl]:0.15CeO2

“…The various model such as: space-charge models, discrete-shell model, pack's model and resister network model etc. [7][8][9][10][11] are suggested for two-phase composite electrolyte system, the reason for the enhancement in the room temperature conductivity with the effect of soaking time is due to increase/decrease in mobile ion concentration or increase/decrease in ionic mobility as a result of creation of high conducting paths interconnecting the different two-phase boundaries [2][3][4]. To find out valid reason for the conductivity enhancement in this system, we carried out direct measurement of ionic mobility (l), using transient ionic current (TIC) technique [22].…”

“…(termed as a first-phase host matrix) [1][2][3][4][5][6]. Various theoretical models such as space-charge models [7], discrete-shell model [8], Pack's model [9], resister network model [10], percolation model [11] and concentration gradient model [12] etc. have been proposed to explain the ion transport mechanism in these systems.…”

Superionic Solids in Energy Device Applications

“…Based on the "continuum space charge theory" of Kliewer, Jow and Wagner proposed the space-charge model to explain σ-enhancements in some two-phase composite electrolyte systems [59,60]. According to them, when the submicron-size particles of dispersoid material (A) are dispersed into the host matrix salt (MX), a space charge region of thickness λ is created around the dispersoid particles embedded in the host salt, as shown in Figure 4.7(a).…”

“…Jow and Wagner's model explained the phenomenon of σ-enhancement as a function of temperature, particle size and volume fraction of the dispersoid, but failed quantitatively. Based on the space-charge concept, Stoneham et al proposed "discrete-shell" and/or a more realistic "screening-layer" model, and explained σ-enhancement in two-phase composite electrolytes, which is, according to them, due to random dispersal of dispersoid particles in the host matrix salt and the existence of high conducting layer on the non-conducting core at the space-charge boundary, as shown in Figure 4.8 [60]. On the basis of Stonhan et al's approach, Pack expressed the total conductivity for explaining σ-enhancement in two-phase composite electrolyte systems by the following equation [61]: (4.19) where G (= σ sc / [S(1-V v )]) accounts for the number of excess charge per unit volume of mixture, S is the surface area created by dispersoid per unit volume of mixture and other symbols have their usual meaning.…”

Effect of alumina on dc ionic conductivity of barium nitrate solid electrolyte

“…If the particle size of insulating material is of the order of microns, then the effect can be described satisfactorily by means of space charge model [1,2]. Various other theories such as average medium approximation [12], Maier's approach [1,13], random resistor model [14] have also been proposed to explain this effect. In order to see such effects of dispersion of inert oxide materials we chose a Frenkel type solid, Ba(NO 3 ) 2 , as a host material and alumina as dispersoid.…”