Investigating the electrical properties of V2O5 modified lithium borate glasses using Dielectric Spectroscopy: Insights into Li+ ion diffusion and mixed conduction for energy storage applications

Abstract

A comprehensive investigation was conducted on the electrical conductivity, electric modulus, and impedance properties of (50–x)Li₂O–xV₂O₅–50B₂O₃ glasses, with x values of 0, 4, 8, 12, 16, and 20 mol%. The study aimed to elucidate the conduction mechanisms and evaluate the potential applications of these materials. AC conductivity investigation using the Almond-West formalism yielded important characteristics including crossover frequency (ω_H), DC conductivity (σ_dc), and frequency exponent (s). The results showed that conduction occurs via a non-overlapping small polaron tunneling process. Furthermore, the imaginary electric modulus, as studied by the Kohlrausch-Williams-Watts function, showed non-Debye relaxation behavior, with compositional effects becoming more significant at higher frequencies.Temperature-dependent impedance investigation and modeling with an analogous circuit indicated that ionic and polaronic conduction, as well as Li⁺ ion diffusion, occurs simultaneously in LVB4, LVB5, and LVB6 glasses. The activation energy estimated from conductivity, electric modulus, and impedance analyses revealed a significant connection, confirming the consistency of the results. The impedance analysis shows that electrical conduction in these glasses happens via a dual mechanism involving Li⁺ ions and electrons/polarons, making them intriguing candidates for energy storage applications.