Enhanced temperature stable dielectric properties and energy-storage density of BaSnO3-modified (Bi0.5Na0.5)0.94Ba0.06TiO3 lead-free ceramics

Abstract

A series of (1-x)(Bi0.5Na0.5)0.94Ba0.06TiO3-xBaSnO3 (BNBT-100xBSN, x = 0–20) lead-free ceramics were synthesized using a conventional high-temperature solid-state reaction route. The effects of BaSnO3 on the dielectric, ferroelectric and energy-storage performance of BNBT-BSN were systematically investigated. Temperature dependent permittivity curves indicated the obviously enhanced relaxor ferroelectric property. The introduction of BaSnO3 reduced the temperature corresponding to the first dielectric anomaly, which facilitated the dielectric temperature stability. △ε'/ε'150°C varied no more than 15% within the temperature range of up to 338 °C (45–383 °C) for BNBT-15BSN. A slimed P-E loop was obtained with the remnant polarization of 0.4 μC/cm2 for BNBT-15BSN. Moreover, the breakdown field intensity of BNBT-BSN increased effectively from 80 kV/cm to 115 kV/cm. Therefore, an optimum energy-storage performance was obtained in BNBT-15BSN with the energy-storage density of 1.2 J/cm3 whose energy-storage efficiency reached 86.7%. Furthermore, the possible contributions of defect and vacancy to relaxation and conductance mechanism were discussed by studying the impedance and electric modulus. The results above indicated the BNBT-100xBSN be a promising lead-free candidate for energy-storage capacitors.