Microstructure tailoring for enhancing the energy storage performance of 0.98[0.6Ba(Zr0.2Ti0.8)O3-0.4(Ba0.7Ca0.3)TiO3]-0.02BiZn1/2Ti1/2O3 ceramic capacitors

Abstract

In this work, we introduce a new approach to enhance the energy storage properties of 0.98[0.6Ba(Zr0.2Ti0.8)O3-0.4(Ba0.7Ca0.3)TiO3]-0.02BiZn1/2Ti1/2O3 [BCZT-BZ] ceramic capacitors via tuning the microstructure through the sintering time. The x-ray diffraction (XRD) analysis confirmed the formation of BCZT-BZ solid solution without any secondary phase. It is observed that the rhombohedral and tetragonal phases co-exist in BCZT-BZ samples sintered at different time periods, except the one sintered for 11 h, where the rhombohedral and pseudocubic phases co-exist. The energy dispersive x-ray spectroscopy (EDS) revealed the presence of the elements constituting the BCZT-BZ samples. The variation of the grain size with the sintering time is explained based on the coalescence process and the Ostwald ripening mechanism. A strong correlation was observed between the ferroelectric properties and the microstructure. The sample sintered for 11 h with pseudocubic nature and small grain size shows a slim P-E loop owing to a high recoverable energy density (2.61 J/cm3) and a high efficiency (91%) at an electric field of 150 kV/cm. The observed recoverable energy density was found 3 to 13 times higher than that reported for bulk BCZT. These findings suggest that the present BCZT-BZ ceramics are attractive materials for the energy storage capacitor applications. Keywords: Ceramics, Relaxor ferroelectrics, Lattice distortion, Grain size, Recoverable energy