Studies on lithium alumino phosphate glasses doped with selenium ions for hard electrolytes

Glass samples of the system (100 - x) (0.5 Li2O-0.2Al(2)O(3)-0.3P(2)O(5)) + xSeO(2) (x is ranging from 0 to 12 mol%, labeled as LAPS (x) ) were prepared using the melt quenching technique. FTIR spectral studies indicate that selenium ions mostly occupy network modifying sites due to isolated selenite (SeO3 (2-)) groups up to 6 mol% of SeO2 (LAPS(6)) in the LAPS glass network. This has a tremendous effect on the electrical properties. Glass forming ability parameter (K (gl)) and the glass transition temperature (T (g)) of LAPS samples were characterized by DTA traces. Electrical measurements were carried out as a function of frequency and temperature over the frequency range of 10 Hz to 10(6) Hz and a temperature range of 303-423 K. The electric modulus formalism was applied to study the relaxation behavior using the impedance data for all the samples at 303 K and also for analyzing the relaxation behavior of the highest conducting sample (6 mol% of SeO2) at different temperatures. An attempt has been made to relate the measured properties to the structural modifications due to the modifying effect of isolated selenite (SeO3 (2-)) groups in the glass network.