Enhanced Energy Storage Density and Efficiency of Lead-Free Bi0.5Na0.5TiO3-SrTiO3 Ferroelectric Ceramics by BaZrO3 Doping ☆

To improve the energy storage density and efficiency of lead-free ferroelectric ceramics, the ternary Bi0.5Na0.5TiO3-SrTiO3-BaZrO3 ferroelectric system was studied. All ceramics were fabricated by a conventional solid-state reaction method and sintered at 1150 oC for 2 h. The crystal structure, electric-field-induced polarization, energy storage density, and efficiency properties of all samples were analyzed. The X-ray diffraction patterns show that the addition of BaZrO3 in the Bi0.5Na0.5TiO3-SrTiO3 system influences a phase transition from tetragonal to a pseudocubic structure. The electric field-induced-polarization loops confirm the phase transition from ferroelectric to relaxor in Bi0.5Na0.5TiO3-SrTiO3-BaZrO3 ceramics, which increases the energy storage density and efficiency of the samples. The energy storage density and efficiency of pure Bi0.5Na0.5TiO3-SrTiO3 (x = 0) were ~ 0.2 J/cm3 and ~ 29%. The addition of 1% BaZrO3 increases the energy storage density and efficiency of the sample to ~0.4 J/cm3 and ~74%. The further increase in the BaZrO3 content to x = 0.03 shows the energy storage density of ~ 0.38 J/cm3 with an energy storage efficiency of ~ 97%. The results indicate promising lead-free ferroelectric ceramic candidates for energy storage capacitor applications.