Effect of manganese doping on structural, optical, morphological, and dielectric properties of Ba(Ti 1-x Mn x )O 3 lead-free ceramics for energy storage in supercapacitors

A supercapacitor (SC) is considered to be one of the best energy storage devices due to its high-power density, long lifespan, fast charge storage capability, and eco-friendliness. Ceramics with low-cost, nontoxic, high efficiency, and stability are the suitable and promising materials for performed supercapacitors at room temperature. As proposal, we synthesized by sol-gel method the ceramics Ba(Ti Mn )O (where x = 0, 1, 2, or 3%) to study the effect a low rate of manganese doping on their morphological, structural, dielectric, and optical properties. The microstructure of the sintered ceramics was examined using scanning electron microscope (SEM), and the results reveal that the average grain size (AGS) of the ceramics (0.663-1.018 μm) increases with increasing Mn doping content. The optical behavior was studied by UV-visible spectroscopy, and the results indicate that Mn doping reduces the band gap (E ) from 3.27 to 2.79 eV thus, the possibility of using these materials in photocatalyze applications. The dielectric properties of all studied samples were investigated at the temperature range 30-400 °C and frequency range 10 -10 Hz. Significant modification in dielectric permittivity and an appreciable decrease in dielectric losses were observed when adding Mn ions to BaTiO ceramics. Variations in dielectric properties and AC conductivity, as a function of frequency, reveal a relaxation mechanism related to the Maxwell-Wagner interfacial polarization. The obtained results suggest the use of prepared ceramics in capacitor and actuator applications at room temperature (RT).