Effects of Sintering Method and BiAlO3 Dopant on Dielectric Relaxation and Energy Storage Properties of BaTiO3–BiYbO3 Ceramics

(0.9 – x )BaTiO 3 –0.1BiYbO 3 – x BiAlO 3 ( x = 0, 0.02, 0.04, and 0.08) lead-free ferroelectric ceramics are synthesized using conventional sintering (CS) and microwave sintering (MWS) methods. The microstructure, dielectric and ferroelectric properties, relaxation behavior, and energy storage properties are investigated systematically. X-ray diffraction (XRD) patterns show a single perovskite phase for all samples. Scanning electron microscope (SEM) images indicate that MWS method can impede the grain growth, whereas the introduction of BiAlO 3 can lead to the increase in the grain size. Dielectric measurements reveal that an obvious dielectric relaxation behavior can be strengthened by MWS, and the improvement of the dielectric constant ( ε r ) of ceramics is realized by MWS. Incorporated with BiAlO 3 contributes to enhancement of the frequency and temperature stabilities of the dielectric constant for BaTiO 3 –BiYbO 3 ceramics. The slim hysteresis loops are observed, and the maximum polarization of the sample sintered by MWS is higher than that sintered by CS. The MWS samples possess a higher energy density which is about 2 times larger than that of CS samples, and the largest energy storage density ≈0.86 J cm −3 and energy storage efficiency ≈97.44% are, respectively, obtained at x = 0 and 0.04 for MWS ceramics.