Relaxor behavior of BaTiO3-BiYO3 perovskite materials for high energy density capacitors

Abstract Dielectric materials with high dielectric constant and breakdown voltage are very promising for pulsed energy storage applications. In this paper, (1-x) BaTiO 3 -xBiYO 3 (x=0–0.5) ceramics were synthesized using conventional solid-state reaction method. The ceramic structure transformed from ferroelectric tetragonal phases (x≤0.5) to pseudo-cubic phases (x≥0.1). When x=0.2, beyond the solid solubility limit of BaTiO 3 -BiYO 3 , the second phase and glassy phases were formed, accompanying lattice parameter excursion. It revealed a gradual change from classic ferroelectric behavior in pure BaTiO 3 to highly diffusive and dispersive relaxor-like characteristics with BiYO 3 content increasing. It exhibited high polarization maximum and low remnant polarization, which was favorable for energy storage in (1-x)BaTiO 3 -xBiYO 3 ceramics, due to the disrupted long polarization, the created weak coupling and the formed second phase. Furthermore, the nonlinearity of the (1-x)BaTiO 3 -xBiYO 3 ceramics were weakened obviously. A maximum energy storage density of 0.316 J/cm 3 at 66 kV/cm with relative high energy efficiency of 82.7% was achieved in 0.8BaTiO 3 -0.2BiYO 3 ceramic, which indicated that (1-x)BaTiO 3 -xBiYO 3 ceramics were promising lead-free relaxor materials for energy storage applications.