Enhanced recoverable energy density of 0.94Bi0.50(Na0.78K0.22)0.50Ti1−x(Fe0.50Nb0.50)xO3–0.06BaZrO3 lead-free relaxor ceramics doped by (Fe0.50Nb0.50)4+ complex ions

Abstract

The innovative 0.94Bi 0.50 (Na 0.78 K 0.22) 0.50 Ti 1−x (Fe 0.50 Nb 0.50) x O 3-0.06BaZrO 3 (BNKTBZ-xFN) lead-free relaxor ceramics were designed and fabricated by the conventional solid-state technique. The dielectric, ferroelectric, energy storage, and impedance performance of these ceramics were investigated systematically. XRD patterns revealed that the (Fe 0.50 Nb 0.50) 4+ complex ions had completely dissolved in the lattice and constructed a single solid-solution. The addition of (Fe 0.50 Nb 0.50) 4+ complex ions had an obvious impact on the grain size and crystallinity of BNKTBZ-xFN ceramics, which led to a large dielectric breakdown strength. In addition, the degree of diffusivity (γ) for BNKTBZ-xFN ceramics were increased from ~ 1.72 to ~ 1.93, indicating an enhanced relaxor behavior with the doping of (Fe 0.50 Nb 0.50) 4+ complex ions. The highest recoverable energy density (W rec) ~ 1.20 J/cm 3 and energy-storage efficiency (η) ~ 72% were attained at 120 kV/cm for BNKTBZ-2FN ceramic with the excellent fatigue resistance. Therefore, the BNKTBZ-2FN ceramic might be a promising candidate for energy-storage electronic devices.

Excellent energy storage performance of (Sc0.5Ta0.5)4+ modified (Bi0.5Na0.5)TiO3-based ceramics modulated by the evolution of polar phases

“…32 With increasing (Sc 0.5 Ta 0.5 ) 4+ content, the external oxygen vacancies continue to increase; accordingly, in order to maintain the equilibrium concentration of oxygen vacancies, the intrinsic oxygen vacancies which can be determined by EPR are inhibited. 33 A similar phenomenon can also be found in Cu/Nb co-doped BTCN, 33 (Y 0.5 Ta 0.5 ) 4+ co-doped BNT-BT 34 and BNKTBZ-0.02FN, 35 ceramics. When x is above 20%, the oxygen vacancy concentration increased with x , which is probably related to the increase in optimized sintering temperature caused by the increased content of Sc 2 O 3 with a high melting point.…”