A study of ionic transport properties on a new Ag+-ion-conducting composite electrolyte system:: (1-x)[0.75AgI:0.25AgCl]:xSiO2

Preparation of a new Ag+-ion-conducting two-phase composite electrolyte system (1 - x)[0.75AgI : 0.25AgCl] : xSiO(2), 0 less than or equal to x less than or equal to 0.5 (in molar weight fraction) and studies of its ionic transport properties are reported. Nano-size (similar or equal to 8 nm) particles of insulating and insoluble SiO2 were used as second-phase dispersoid particles, while a new compound, 'a quenched/annealed [0.75AgI :0.25AgCl] mixed-system/solid solution', recently investigated in the present laboratory, was used as the first-phase host matrix in place of the conventional host salt AgI. Various routes of sample preparation were adopted. The composition 0.9[0.75AgI : 0.25AgCl] : 0.1SiO(2) exhibited the highest enhancement (similar or equal to 10(1)) in the room-temperature conductivity from that of the host. We referred to this as the 'optimum conducting composition (OCC)' with room temperature conductivity about 10(-3) S cm(-1). The coexistence of constituent phases was confirmed by x-ray diffraction (XRD) and differential scanning calorimetry (DSC) studies. Various ionic transport parameters, namely the conductivity, mobility, mobile-ion concentration, transference number and drift velocity of the conducting ion, were measured experimentally as functions of the temperature. The results have been explained on the basis of theories proposed for two-phase composite electrolyte systems.