Investigation of structure, morphology, dielectric, electrical, and electrochemical properties of Sr-doped BCZT perovskites

Abstract

In this study, we synthesised (Barium Calcium Zirconate Titanate) BCZT and Sr-doped BCZT (Strontium doped Barium Calcium Zirconate Titanate) perovskites using the hydrothermal technique. The samples sintered at 600, 700, and 800 °C to analyse the effect of temperature on their structure, dielectric, electric, and electrochemical properties. The crystallite size obtained thorough XRD analysis is 23 ± 0.5 nm and FESEM micrographs revealed the formation of spherical grains which further corroborated by TEM micrographs. The dielectric loss ranges between 0.05 and 0.42 for all the samples which indicates the satisfactory contact formation. Nyquist plots show that a clear semi-circular arc is not formed in any of the samples, which is because of their highly resistive nature. DC resistivity results showed that with an increase in sintering temperature, the PTCR behaviour is observed to improve which suggests an increase in insulating or dielectric properties of the materials. For undoped BCZT, at around 50 °C the resistivity decreased with an increase in sintering temperature. The AC conductivity findings indicate the existence of space charge polarisation at low frequencies and mobile ionic species at high frequencies. The DC resistivity findings indicated that B1 and Bs1 exhibited the maximum conductivity at room temperature, whereas resistivity rose with increasing temperature, indicating PTCR behaviour for all samples. The CV analysis indicated that the greatest values of Cs, E, Qs, and q are recorded for Bs1, measuring 0.541 F/g, 0.59 Wh/kg, 0.000759 mAh/g, and 1.517 C, respectively, at a scan rate of 0.09 mV/s, while the second highest values are noted for Bs1, followed by B1. The results suggested that by regulating the processing temperature, the cation and anion vacancies may be effectively managed, leading to the targeted application of pristine and Sr-doped BCZT. This also indicates the versatile characteristics of BCZT-related materials, including applications from temperature sensors to electrochemical sensors. Thus, by utilising the obtained results, a multifunctional perovskite material could be developed using low-temperature synthesis method.