Electronic to ionic conductivity of glasses in the Na2O-V2O5-TeO2 system

Glasses in the 2TeO(2)xNa(2)O(1 - x)V2O5 system have been synthesized for 0 less than or equal to x less than or equal to 1. Glass transition temperatures are between 220 degrees C and 250 degrees C. Conductivity data obey an Arrhenius type behaviour for temperatures ranging from room temperature to below their glass transition temperatures. Values of activation energies and pre-exponential factors in the V2O5 rich region are low compared to those in the Na2O rich region, implying that the conductivity mechanisms in these two regions are different. Experimental data suggest that a polaron hopping mechanism operates in the electronically conducting domain of 0 less than or equal to x < 0.5 and an interstitial pair mechanism operates in the ionically conducting domain of 0.5 < x less than or equal to 1.