Dielectric characteristics, dipolar relaxation dynamics and ac conductivity of CuO added lithium sulpho-phosphate glass system

• Published in: Journal of non-crystalline solids 2020-09, Vol.543, p.120157, Article 120157
• Main Authors: Sekhar, A. Venkata, Pavić, L., Moguš-Milanković, A., Purnachand, N., Reddy, A. Siva Sesha, Raju, G. Naga, Veeraiah, N.
• Format: Article
• Language: English
• Subjects: Ac conductivity; Cu ions; Dielectric properties; Dipolar relaxation; Lithium sulpho-phosphate glasses
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2020.120157

•Influence of CuO on dielectric features of Li2SO4−MgO-P2O5 glasses is investigated.•Spectroscopic studies revealed the presence of a mixed valance state of copper in studied glasses.•Dielectric parameters and conductivity exhibited a decreasing trend with CuO content.•Dipolar effects exhibited by electric moduli spectra were analyzed by Cole-Cole plots.•In the glasses with a higher content of CuO, polaron conduction is prevalent. In this work we have investigated the influence of copper ions on dielectric characteristics and ac conductivity of lithium sulpho magnesium phosphate glasses. Glass samples were synthesized by melt-quenching and annealing methods. The structural analysis of the glasses is performed by XPS, optical absorption (OA) and IR spectral studies. The XPS and OA spectral studies have revealed increasing fraction of Cu+ ions in the glasses, whereas IR spectral results indicated a growing degree of internal augmentation between various structural units the glass network with increase of CuO content. The dielectric parameters and a.c. conductivity, σac, exhibited decreasing trend while electrical impedance showed an increasing trend with increase of CuO concentration. The dipolar effects exhibited by electrical moduli dispersion spectra were analyzed by Cole-Cole plots. The increased degree of rigidity of the glass network is predicted to be responsible for the observed decrease of σac. The overall analysis of the variation of σac with CuO content indicated a gradual increment in the polaronic component at the expense of ionic component of conductivity. Finally, it is concluded that the studied glass doped with a small concentration of CuO is as useful as electrolyte material in solid-state batteries, whereas higher concentration of CuO is detrimental for such applications.