Impact of Cr3+/Mo6+/W6+ Doping on Dipolar Relaxation and AC Conductivity in Li2O–Al2O3–SiO2 Glasses

Abstract

In this investigation, results of dielectric features of Li2O–Al2O3–SiO2 (LAS) glass doped with 3.0 mol% of Cr2O3, MoO3, and WO3 are presented. The investigation spans broad regions of frequency (ω) 10−2–106 Hz and temperature (T) 20–240 °C. Initial characterization of the samples by means of optical absorption spectra reveals that Cr ions do persist in Cr3+oxidation state, whereas fractions of Mo and W ions do present in Mo5+ and W5+ states in addition to predominant presence Mo6+ and W6 + ions, respectively. Infrared spectra suggest that Mo5+ and W5+ ions involve in modifying the network of the glass and induced structural disorder. Dielectric parameters and also σac are observed to be the largest for 40Li2O–5Al2O3–52SiO2:3.0 MoO3 (LASMo) glass followed by 40Li2O–5Al2O3–52SiO2:3.0 WO3 (LASW) and 40Li2O–5Al2O3–52SiO2:3.0 Cr2O3 (LASCr) glasses. Analysis of dipolar relaxation phenomena are carried out using Cole–Cole plots. Analysis of the results of σac suggests that polaronic conduction due to electron transfer between Mo5+ ↔ Mo6+ and W5+ ↔ W6+ is prevailed in case of LASMo and LASW glasses and these glasses are predicted to be useful as cathodes, whereas in LASCr glass, ionic conductivity is dominant and is suitable for electrolytes in ionic batteries.