2026 | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008
The effect of polyvinyl alcohol (PVA) addition on structural, electrical and dielectric properties of MnCo2O4 cobaltite system
Authors: Dhahri, A.; Moualhi, Y.; Zaouali, A.; Costa, BFO
Ref.: Ceram. Int. 51(24) B, 42973-42989 (2025)
Abstract: In this research work, we investigate the structural, microstructural, electrical and dielectric properties of MnCo(2)O4(/)x-percentage Polyvinyl Alcohol (PVA) (x = 0, 10 and 30) oxides that were successfully synthesized by the sol-gel method and embedded in PVA matrix by mechanical alloying. The X-ray diffraction analysis demonstrated that the samples crystallize in the cubic system with Fd 3 m space group. After doping the MnCo2O4 by PVA, the stability factor "t" has increased and became close to unity. The PVA concentration increase is accompanied by a crystallite size decrease from 50 to 33 nm and a porosity increase from 11 % to 30 %. The small particle size and narrow size distribution of MnCo2O4 powders were enhanced using PVA addition. The DC conductivity study shows that all samples, at different PVA concentrations, exhibit a semiconductor character. The mentioned behavior is linked to the activation of two different kinds of hopping mechanisms (the small polaron hopping at high temperatures and the variable range hopping mechanism at low temperatures). At room temperatures, it is found that the incorporation of PVA into MnCo2O4 particles has enhanced the electrical conductivity. The AC conductivity spectra of MnCo2O4/x percentage PVA system were investigated using the Jonscher law and the Drude model. From the Nyquist plots, we found that the electrical and dielectric responses of the samples were governed by the contribution of conductive grains at elevated frequencies and resistive grain boundaries at low frequencies. At 300 K, we found that doping MnCo2O4 matrix by PVA improves mainly the dielectric characteristics of MnCo2O4. Accordingly, it is observed that MnCo2O4/30 % PVA sample proves to be powerful candidate since it presents the highest values of conductivity (3.10(-3) S m(-1)) and dielectric constant (2.4 10(3)) at room temperature. From this perspective, we can assume that MnCo2O4/30 % PVA can be considered a new class of energy storage material for electrical devices.
