Ionic and polaronic conduction in mixed ionic-electronic 98[20Li2O-xBi2O3-(80-x)TeO2]-2Ag glass system

• Published in: IONICS
• Main Authors: Sutrisno, M. S.; Hisam, R.
• Format: Article
• Language: English
• Published: SPRINGER HEIDELBERG 2024
• Subjects: Chemistry; Electrochemistry; Physics
• Online Access: https://www-webofscience-com.uitm.idm.oclc.org/wos/woscc/full-record/WOS:001140071000043
• ISSN: 0947-7047; 1862-0760
• DOI: 10.1007/s11581-023-05301-7

The ionic and polaronic conduction in mixed ionic electronic 98[20Li(2)O-xBi(2)O(3)-(80 - x)TeO2]-2Ag (x = 3, 5, 7, 11, 13, and 15 mol%) glasses had been analyzed with several theoretical models. The anomalous drop in log sigma DC for the investigated glass samples from x = 7 mol% to x = 11 mol% can be attributed to mixed ionic electronic effect (MIE) effect. The minimum in the MIE region is suggested to be due to a blocking effect on Li+ ion migration throughout the glass matrix. According to Almond-West formalism, the blocking Bi3+ ions to Li+ ions may induce high activation energy required for the formation of mobile carriers E-C at x = 7 mol%, reducing the mobile Li+ ions available for ionic DC conductivity. Meanwhile, in ionic diffusion model, the blocking of Li+ ions may reduce the defect site concentration n at x = 11 mol% causing Li+ ions to migrate more slowly through the percolation channels. Anderson-Stuart activation energy EA analysis revealed that the accumulation of large BiO6 units in interstitial sites due to blocking effect may provide smaller size of interstitial openings for Li+ ions hence requiring high strain energy E-S for ionic migration through the glass network. In addition, in the small polaron hopping model, the high number of BO units at x = 7 and 11 mol% may result in a decrease in density of states near Fermi level N(E-F). The decrease in N(E-F) may induce high activation energy W required for polaron hopping. Nonetheless, polaron hopping energy W-H had a lower influence on total activation energy W than disordered energy W-D, indicating that structural changes (BO/NBO formation) play a significant role in the polaron hopping mechanism.