Electrical and electrochemical properties of a new silver tungstate glass system:: x[0.75AgI: 0.25AgCl]: (1-x)[Ag2O: WO3]

Investigations on electrical and electrochemical properties of a new silver tungstate glass system: x[O.75AgI: 0.25AgCl]: (I - x)[Ag2O: WO3], where 0.1less than or equal toxless than or equal to1 in molar weight fraction, are reported. A "quenched [0.75AgI: 0.25AgCl] mixed system/solid solution" was used as a host salt in place of the traditional host AgI for synthesizing the glass system. Compositional variation of room temperature conductivity of the glass systems prepared identically using both the new and traditional hosts exhibited sigma-maxima at x=0.7. The composition: 0.7[0.75AgI: 0.25AgCl]: 0.3[Ag2O: WO3] shows the highest room temperature conductivity (sigma(27 degreesC)=4.0 x 10(-3) S cm(-1)) and has been referred to as optimum conducting composition (OCC). Formation of glass in the OCC was confirmed by X-ray diffraction (XRD) and differential thermal analysis (DTA). A direct determination of ionic mobility (mu), was done by transient ionic current (TIC) technique, subsequently, mobile ion concentration (n) was evaluated using sigma and mu data. An increase in mu has been ascribed as the reason for the enhancement in the room temperature conductivity as compared to pure host. Temperature dependence of ionic parameters, namely, alpha, mu, n, ionic transference number (t(ion)) and ionic drift velocity (v(d)) was carried out on the OCC sample only and the mechanism of ion transport has been discussed in the light of models suggested for superionic glasses. The electrochemical study on solid state batteries, fabricated using OCC as electrolyte with Ag-metal as anode and C + I-2 as cathode, exhibited a satisfactory performance during low current drain. (C) 2004 Elsevier B.V All rights reserved.