Fast Protonic Conducting Solid Electrolytes

Theoretical and experimental research on glassy and crystalline solid electrolytes materials has been pursued. In lithium aluminum silicate we found that the presence of disorder in the aluminosilicate framework can exert substantial effects on the conductivity of the lithium ion; in particular the activation energy for ionic motion is substantially lower in the glassy phase than in the crystalline one, despite the greater disorder in the glass. This was explained in terms of reduced effects of interionic correlation in the disordered material compared to the rigidly alternating crystal. This substantial reduction in the localizing effects of ionic correlations should be operative in all glasses, and may account for enhancements of conductivity in stoichiometric glass compositions at relatively low temperatures. Complex impedance spectroscopy, magnetic resonance, vibrational spectroscopy and differential anomalous scattering techniques have been used to study local structures in silver selenide-germanium selenide glasses. The data seems to show the coexistence of well-defined local order with typical glassy randomness. Diffusion measurements on both uranyl phosphate and beta alumina protonic electrolytes were completed using nuclear magnetic resonance spectroscopy. The results strongly suggest that the sample for the Grotthus mechanism is not operative here. A detailed study of the transport properties of the proton conducting hydrogen-uranyl-periodate-water glasses was made. Keywords: Solid electrolyte, Conductivity, Dynamic percolation, Diffusion.