High-entropic relaxor ferroelectric perovskites ceramics with A-site modification for energy storage applications

Abstract

With the growing concept of developing smart cities, the demand for evolving eco-benign and efficient energy storage applications with extraordinary performance has risen significantly. To overcome such high demands, configurationally complex composites/alloys are engineered by populating the single lattice site of perovskite materials deliberately with distinct cations to create highly entropic form of materials. Herein, two high entropy ceramics (Ba0.2Na0.2Ca0.2Sm0.2Bi0.2)TiO3 (BNCSBT) and (Ba0.2Na0.2Mg0.2La0.2Bi0.2)TiO3 (BNMLBT) are deliberately engineered to analyze their structural, ferroelectric and dielectric capacitive performance. XRD analysis, tolerance factor and Rietveld refinement of measured XRD patterns of the ceramics have confirmed the Cubic symmetry with Pm3‾m space group. Both BNCSBT and BNMLBT ceramics have demonstrated the maximum polarization (Pmax) of 26.3 μC/cm2 and 28. 02 μC/cm2, recoverable energy density (Wrec) of 1.0715 J/cm3 and 1.1225 J/cm3 and energy conversion efficiency (ƞ) of 81.42% and 80.12% respectively. Moreover, the temperature dependent dielectric analysis of BNCSBT and BNMLBT ceramics has presented the wide transition temperature effect due to the creation of polar nano-regions, confirming the relaxor ferroelectric behavior with diffusion coefficient values of 1.8312 and 1.8021 respectively. Such engineered high-entropic ceramics with excellent relaxor ferroelectric and dielectric capacitive performances even at the high temperature (120 °C) are phenomenal for temperature dependent energy storage applications.