Enhanced energy storage properties and excellent fatigue resistance of Pb-free Bi0.47Na0.376K0.094Ba0.06Nb0.024Ti0.97−x(Ta0.24Sn0.7)xO3 relaxor ceramics

Abstract

Pb-free Bi0.47Na0.376K0.094Ba0.06Nb0.024Ti0.97−x(Ta0.24Sn0.7)xO3 perovskite ceramics were prepared using a mixed-oxide reaction technique, and their structural, dielectric, ferroelectric, and energy storage properties were systematically investigated. All the compositions exhibited a pseudo-cubic perovskite crystal structure with a highly dense morphology. The doping of complex ions (Ta0.24Sn0.7)4+ disturbed the long-range ordering, which reduced the ferroelectric-to-relaxor phase transition temperature to room temperature. Hence, the modified ceramics exhibited relaxor behavior in their polarization and current density versus applied field plots. Owing to the excellent field-induced ferroelectricity and facile reversibility of ferroelectric-relaxor phase transition of polar nanoregions (PNRs), a high recoverable energy density of 1.65 J/cm3 with a good efficiency of 77.69% was achieved under 125 kV/cm at x = 0.03. In addition, the ceramic with x = 0.03 showed a high recoverable energy density of 1.01 J/cm3 with a high conversion efficiency of 84.22% at 70 °C under 80 kV/cm and fatigue-free characteristics during 105 cycles, demonstrating the highly dynamic and very stable nature of PNRs and very few ionic defects in the grains. Therefore, such ceramics (x = 0.03) are expected to be suitable for high-energy-density materials in electronic industries.