Energy storage properties of BNT-BT based solid solution

The phase structure, microstructure, dielectric and energy storage properties of 0.85(0.92Bi_0.5Na_0.5TiO₃-0.08BaTiO₃)-0.15(Na_1-3xBi_xNbO₃) (BNTBT-NB_xN) polycrystalline lead-free ceramics were systematically investigated. Dense and pore-free samples were prepared by conventional solid state reaction method. X-ray diffraction results indicated that the solid solubility of Bi in BNTBT-NB_xN system lay at x=0.05~0.07. Within the solid solubility, the first dielectric anomaly which located at temperature T_s was depressed and shifted towards lower temperature with x increasing. As a consequence, the temperature stability of dielectric properties was largely improved, which demonstrated that BNTBT-NB_xN ceramics were promising for high-temperature capacitor dielectrics. The ferroelectric properties analysis indicated that with the increase of x, the maximum polarization P_m gradually reduced and the P-E loops became slant and slim. The optimum energy storage properties was obtained for x=0.05 with energy storage density W=1.29J/cm³ and energy storage efficiency η=76%.