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    Modified energy storage properties of lead-free Sr0.3Bi0.35Na0.335Li0.015TiO3 ceramics with La3+ substitution via the solid-state combustion technique
    (2024-12-01)
    Sinkruason, Thanapon
    ;
    Luangpangai, Anupong
    ;
    Julphunthong, Phongthorn
    ;
    Rittidech, Aurawan
    ;
    Suthapintu, Aekasit
    In this study, the influence of La<sup>3+</sup> substitution on the phase structure, microstructure, electrical and energy storage properties of (Sr<inf>0.3</inf>Bi<inf>0.35</inf>Na<inf>0.335</inf>Li<inf>0.015</inf>)<inf>1-x</inf>La<inf>x</inf>TiO<inf>3</inf> (SBNLT-xLa) ceramics with x = 0–0.05, using the solid-state combustion technique, was investigated. X-ray diffraction (XRD) patterns indicated a pure perovskite structure formed, along with coexisting rhombohedral and tetragonal phases in all ceramics. The Rietveld refinement analysis showed the tetragonal phase increased while the rhombohedral phase decreased with increased La<sup>3+</sup> content. The morphology of the SBNLT-xLa ceramics displayed polygonal grain shapes and anisotropic grain growth. Average grain sizes increased from 2.01 to 2.43 μm as x increased from 0 to 0.01 and afterwards decreased as x increased further. Both the measured density and maximum dielectric constant (ɛ<inf>m</inf>) decreased from 5.48 to 5.29 g/cm<sup>3</sup> and from 4667 to 2313, respectively, when x increased from 0 to 0.05. A decrease in the dielectric properties caused by the phase ratio shifting away from a morphotropic phase boundary (MPB) condition, poor microstructure and low density was produced with La<sup>3+</sup> replacement. The maximum polarization (P<inf>max</inf>), remnant polarization (P<inf>r</inf>) and coercive field (E<inf>c</inf>) decreased with increased La<sup>3+</sup> content. A decline in P<inf>r</inf> and E<inf>c</inf> improved the energy storage efficiency (ƞ) and energy storage loss (W<inf>loss</inf>), resulting in enhanced energy storage properties. At x = 0.02, the ceramic showed good energy storage properties (W<inf>total</inf> of 0.781 J/cm<sup>3</sup>, W<inf>rec</inf> of 0.624 J/cm<sup>3</sup>, W<inf>loss</inf> of 0.157 J/cm<sup>3</sup> and ƞ of 79.8%), measured at 60 kV/cm.
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    Phase structure, microstructure, electrical and energy storage properties of SBNLT lead free ceramics with Zr4+ substituted into B-sites
    (2024-09-01)
    Sinkruason, Thanapon
    ;
    Luangpangai, Anupong
    ;
    Julphunthong, Phongthorn
    ;
    Rittidech, Aurawan
    ;
    Pulphol, Phieraya
    Lead-free (Sr<inf>0.3</inf>Bi<inf>0.35</inf>Na<inf>0.335</inf>Li<inf>0.015</inf>) (Ti<inf>1−x</inf>Zr<inf>x</inf>) O<inf>3</inf> ceramics (SBNLT<inf>1−x</inf>Zr<inf>x</inf>) with x = 0–0.04 were prepared via the solid-state combustion technique using glycine as the fuel. The influence of Zr content on the phase structure, microstructure, electrical properties, and energy storage properties of the SBNLT<inf>1−x</inf>Zr<inf>x</inf> ceramics was examined. The presence of a pure perovskite phase was shown by X-ray diffraction (XRD) patterns, with the coexistence of rhombohedral and tetragonal phases in all samples, as certified by the Rietveld refinement method. Scanning electron microscopy (SEM) was utilized to observe the morphology of the SBNLT<inf>1−x</inf>Zr<inf>x</inf> ceramics, which revealed cube shaped grains with anisotropic growth. Average grain size increased from 2.01 to 2.49 µm when x increased from 0 to 0.01 and then reduced with further increases in Zr content. The maximum dielectric constant dropped from 4667 to 2990 when x increased from 0 to 0.04, caused by a shift from the morphotropic phase boundary (MPB). The maximum polarization (P<inf>max</inf>) of 29.18 µC/cm<sup>2</sup>, energy storage density (W<inf>total</inf>) of 0.851 J/cm<sup>3</sup> and recoverable energy storage (W<inf>rec</inf>) of 0.609 J/cm<sup>3</sup> were achieved when x = 0.02.
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    Improvement of phase structure and energy storage properties of [(0.72-x)Bi0.5Na0.5TiO3-0.28SrTiO3-xBaZr0.05Ti0.95O3] lead-free ceramics
    (2022-01-01)
    Panpho, Phakakorn
    ;
    Thongmee, Navavan
    ;
    Mathrmool, Krailas
    ;
    Unruan, Muangjai
    ;
    Vitayakorn, Narathip
    Lead-free [(0.72-x)Bi<inf>0.5</inf>Na<inf>0.5</inf>TiO<inf>3</inf>-0.28SrTiO<inf>3</inf>-xBaZr<inf>0.05</inf>Ti<inf>0.95</inf>O<inf>3</inf>] ceramics (abbreviated as BNT-ST-xBZT), x = 0, 0.03, 0.05, 0.07, 0.10, and 0.15 wt.%, were prepared by conventional solid-state reaction method. The effect of x(BZT) content on phase structure, microstructure, dielectric, ferroelectric, and energy storage properties of BNT-BT-x(BST) ceramics was studied. The samples of the study were analyzed through X-ray diffraction (XRD). The XRD patterns were analyzed using Rietveld refinement. The XRD revealed a single-phase perovskite for all the samples with coexisting rhombohedral and tetragonal phases. It shows the increasing of x(BZT) content and, more tetragonal distortion of the phase. The scanning electron micrographs (SEM) of all the samples displayed spherical-like morphology. The grain growth inhibited by increasing of x(BZT) content. The average of grain size decreased from 2.74 µm to 0.65 µm with BZT content. The highest density (ρ = 5.31 ± 0.11 g/cm<sup>3</sup>), recoverable energy storage density (W <inf>rec</inf> = 0.234 J/cm<sup>3</sup>), and energy storage efficiency (η = 90%) at 30 kV/cm were found in the composition of x(BZT) = 0.05 wt.%.