Simultaneously enhanced of energy storage and energy harvesting performances of [(Bi<sub>0.5</sub>Na<sub>0.5</sub>)TiO<sub>3</sub>–BaTiO<sub>3</sub>] ceramics by addition of SrTiO<sub>3</sub>
Amira A. Kamal, S. A. Hussein, Adel Helmy Salem, Abd El-razek Mahmoud
Abstract
Abstract As is well known, relaxor dielectrics are characterized by high energy storage efficiency ( η ), while high recoverable energy storage density (W rec ) can be achieved by anti-ferroelectric ceramics. Herein, our approach is to find relaxor- anti-ferroelectric coexistence phases of (Bi 0.5 Na 0.5 )TiO 3 - BaTiO 3 ceramics for achieving high performance in energy storage and energy harvesting as well. Therefore, [(0.9-x) ( Bi 0.5 Na 0.5 )TiO 3 -xSrTiO 3 -0.1BaTiO 3 ] (abbreviation (0.9-x) NBT-0.1BT-xST) (0.0 ≤ x ≤ 0.4) were synthesized via the solid-state reaction route in air. The tolerance factor ( τ ) increased from 0.9901 to 0.9998 when ST-content increased from 0.0 to 0.4, indicating an increase in crystal lattice symmetry. The FT-IR de-convolution vibration modes shown in the TiO 6 octahedra exhibit two peaks at ∼550 and 650 cm −1 , which indicate present coexistence phases of the crystal structure. Ferroelectric to relaxor phase crossover has been detected by the addition of ST with the present anti-ferroelectric phase in particular dopant ST = 0.2. The increasing into the diffused phase transition ( γ ) is signified by enhancement of the relaxor degree of NBT-BT at high content of ST. The rapidly suppressed remnant polarization (P r ) at high content of ST is due to substitute iso-valence (Sr 2+ ) by tri-valence (Bi 3+ ) and mono-valence (Na 1+ ). Ultrahigh <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>W</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="italic">rec</mml:mi> </mml:mrow> </mml:msub> </mml:math> = 1.13 J/ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">cm</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="1em"/> </mml:math> with excellent η = 92.62% were obtained at ST = 0.3 at low electric field (E = 110 kV cm −1 ). A remarkable response of the strain with a high converse piezoelectric coefficient ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>d</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>33</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>*</mml:mo> </mml:mrow> </mml:msubsup> </mml:math> = 390.47 pm V −1 ) at ST = 0.2 was obtained due to decreasing the non-revisable 180° domain switching. Based on the obtained results, the addition of ST to NBT-BT ceramics can provide a head start in the implementation of ceramic capacitors for potential effective into energy harvesting and energy storage applications.