Exploring dielectric relaxation and AC conductivity of layered double hydroxides

In this study, we present impedance spectroscopy measurements on Zn–Al layered double hydroxides (LDH) with chloride (Cl⁻) as the interlayer anion and a Zn/Al molar ratio of 2:1. Electrical properties, including conductivity, modulus, and dielectric permittivity, were examined over a temperature range of 298–363 K and a frequency (F) range of 200 Hz to 1 MHz. Our findings indicate that electrode polarization significantly influences the relaxation processes within the material. Peaks observed in the imaginary components of permittivity and modulus suggest the presence of relaxing dipoles, with these peaks shifting to higher frequencies as temperature increases, implying a reduction in relaxation time. The AC conductivity generally adheres to Jonscher’s universal power law, with minor deviations. The distinct activation energies obtained confirm that the transport mechanism in this compound is not governed by simple hopping. To further elucidate the conduction mechanism, we applied the non-overlapping small polaron tunneling model, which provides a quantum mechanical framework for understanding the AC conductivity and its F dependence. These findings contribute to a deeper understanding of the electrical behavior of LDH materials, which can be crucial for optimizing their performance in applications such as energy storage, electronics, and potentially in the development of advanced materials for solar cells.