| Summary: | The ionic and polaronic conduction in mixed ionic electronic 98[20Li2O-xBi2O3-(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 logσDC 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 EC 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 ES 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(EF). The decrease in N(EF) may induce high activation energy W required for polaron hopping. Nonetheless, polaron hopping energy WH had a lower influence on total activation energy W than disordered energy WD, indicating that structural changes (BO/NBO formation) play a significant role in the polaron hopping mechanism. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
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