Electrical properties of glasses in the AgI–Ag2O–V2O5–P2O5 system, which in general case exhibit mixed electronic–ionic conduction, were investigated. By thorough adjustment of the composition we have prepared glasses with comparable electronic and ionic contributions to the electrical conductivity. The measured impedance spectra of these glasses indicate the important role of diffusion processes in charge transport. The spectra were analyzed numerically using an electrical equivalent circuit consisting of parallel electronic and ionic branches. The substantial role in the equivalent circuit is played by Warburg elements representing finite-length and semi-infinite diffusion phenomena occurring close to the electrodes.

Mixed conductive silver vanadate–phosphate glasses were prepared and their electrical properties were studied. Compositions of the glasses were characterized by parameters: x (AgI content) and r=[Ag2O]/[V2O5+P2O5]. Total conductivity σt (x, r=constant) of a series of samples with fixed r values exhibited minima when plotted vs. x. The conductivity minima were accompanied by maxima of apparent activation energy Et (x, r=constant). The observed dependencies were attributed to the ion–polaron effect (IPE), i.e. to electrostatic attraction between mobile species: electrons (polarons) and Ag+ ions.

Electrical and electrochemical properties of the glasses of the AgI–Ag2O–V2O5–P2O5 system were characterized by impedance spectroscopy and cyclic voltammetry. The observed correlation between the results obtained by these two methods was analyzed. It was found that for compositions with high content of V2O5 and low of Ag2O and AgI, samples are electronic conductors. For these compositions, voltammograms are linear. At higher contents of AgI, when glasses become electronic–ionic conductors, impedance spectra contain Warburg-like diffusional part and voltammograms reveal some hysteresis. Finally at high contents of AgI and Ag2O impedance spectra indicate blocking effects at the electrodes. Voltammograms of these glasses contain anodic and cathodic peaks.

Three families of mixed conductive silver-vanadate–phosphate glasses have been studied by electron paramagnetic resonance (EPR) spectroscopy. The EPR spectra are sensitive to glass modifier (Ag2O) to network former (V2O5–P2O5) ratio r. For r values close to 1, the hyperfine structure (hfs) of the EPR bands is observed. The presence of a hfs is an indicator of the glass network disruption. Therefore, its absence may indirectly point on enhanced electron hopping between aliovalent vanadium centers along V4+OV5+ bonds. A method was proposed to extract hfs from apparently unresolved EPR spectra. Using a simulation procedure the parameters of a Hamiltonian responsible for interaction between spins of 3d1 electron and 51V nucleus, were determined and a local order around vanadium ions was proposed.

Four different series of AgI–Ag2O–V2O5–P2O5 glasses have been prepared, in a wide range of compositions defined by the ratio of r=[Ag2O]/[V2O5+P2O5] and a parameter x (mol.% of AgI). DTA and Raman scattering experiments reveal that the glass-networks of the investigated glasses are determined mainly by r values, and the x (up to 40%) parameter plays a secondary role. EPR spectra show that the interactions between vanadium centers (which are essential for electronic hopping) strongly depend on crosslinking of the glass network. They dramatically weaken if the glass-network is broken by addition of a large amount of a glass-modifier (Ag2O). Depending on values of r and x the character of electric conduction of the studied glasses changes from purely electronic through mixed to predominantly ionic (via Ag+ cations).

A series of silver–vanadate–phosphate glasses of the AgI–Ag2O–V2O5–P2O5 system has been prepared and their electrical properties have been studied. Compositions of high AgI content and low V2O5 content exhibited pure ionic conduction. On the other hand, vanadium-rich and silver-poor glasses were almost pure electronic conductors, for which, depending on temperature, the models of phonon-assisted hopping of small polarons or variable range hopping can be applied. Samples of intermediate compositions exhibited mixed ionic–electronic conductivity. The observed transition from ionic- to electronic-type conduction in the frame of the same system could be of interest for possible practical applications, e.g. in integrated microbatteries.

The mixed electronic-ionic conducting glasses of the AgIAg2OV2O5P2O5 system have been prepared. XRD and DTA analyses have confirmed the amorphous nature of these glasses. DTA analysis was used to determine glass transition and recrystallization temperatures. EPR measurements showed that at the V2O5-rich end of the compositions, the number of V4+ ions, essential for electronic conduction, is considerable. Electrical properties have been studied using complex immittance spectroscopy. Numerical analysis of the admittance spectra showed that the ionic transference number at the AgI-rich end of the compositions is close to one and for the compositions with high V2O5 content it is considerably lower.