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High energy storage density and stable fatigue resistance of Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 ceramics
Journal Pre-proof High energy storage density and stable fatigue resistance of Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 ceramics Arun Kumar Yadav, Huiqing Fan, Benben Yan, Chao Wang, Mingching Zhang, Jiangwei Ma, Weijia Wang, Wenqiang Dong, Shuren Wang PII:
S0272-8842(19)33193-1
DOI:
https://doi.org/10.1016/j.ceramint.2019.11.015
Reference:
CERI 23384
To appear in:
Ceramics International
Received Date: 29 October 2019 Revised Date:
1 November 2019
Accepted Date: 3 November 2019
Please cite this article as: A.K. Yadav, H. Fan, B. Yan, C. Wang, M. Zhang, J. Ma, W. Wang, W. Dong, S. Wang, High energy storage density and stable fatigue resistance of Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 ceramics, Ceramics International (2019), doi: https:// doi.org/10.1016/j.ceramint.2019.11.015. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Ltd.
High Energy Storage Density and Stable Fatigue Resistance of Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 Ceramics Arun Kumar Yadav a, Huiqing Fan a, b, c *, Benben Yan a, Chao Wang a, Mingching Zhanga, Jiangwei Maa, Weijia Wang a, Wenqiang Dong b, Shuren Wang c a
State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China
b
Institute of Culture and Heritage, Northwestern Polytechnical University, Xi'an 710072, China c
International Joint Research Laboratory of Henan Province for Underground Space
Development and Disaster Prevention, Henan Polytechnic University, Jiaozuo 454001, China *Corresponding author: [email protected], [email protected] Abstract Energy density and fatigue resistance properties were investigated for lead-free Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 (for 0 ≤ x ≤ 0.15) ceramics, synthesized via solid-state reaction technique. Perovskite pseudo-cubic crystal structure was revealed for all ceramics using X-ray diffraction. Polarization and current density versus electric field were perceived and suggested the relaxor behavior with increasing composition. A high storage energy density ~1.58 J/cm3, and conversion efficiency ~71.7 % at ~110 kV/cm applied field was obtained for x = 0.03 composition at room temperature. Energy storage density was revealed ~ 1.53 J/cm3, and efficiency ~ 88.6 % at 110 °C with a 100 kV/cm applied field. In addition, ceramic x = 0.03 was fatigue-free from 1 to 105 cycles. Hence, the composition x = 0.03 might be applicable for high energy storage devices.
Keywords: Perovskite; Lead-free ceramics; Relaxor ferroelectrics; Energy storage properties; Fatigue resistant 1. Introduction With increasing the capacitor’s demand in the area of pulsed power applications, particularly dielectric capacitors with large storage density purposes have been 1
investigated widely, and explored for important functions [1, 2]. Dielectric ceramics have many advantages such as rapid charge-discharge rate, high mechanical strength, and temperature properties, etc. Also, it has one significant drawback of low energy storage density compared to other known energy storage systems like batteries and fuel cells, etc. Currently, high storage density and large thermal range stability for dielectric capacitor materials have attracted considerable attention. Dielectric ceramics for energy density are especially four types such as ferroelectrics, linear dielectrics, relaxor ferroelectrics, and antiferroelectrics [3, 4]. Linear dielectric has high storage efficiency but low energy density. Ferroelectric is known for large remnant polarization (Pr) and high hysteresis loss. Antiferroelectric and relaxor materials are recognized for large storage energy density and conversion efficiency (η) [5]. To plan for large storage density dielectric capacitors required low remnant polarization, large maximum polarization (Pmax), and high dielectric breakdown strength, etc. [6]. Seeing these necessities, antiferroelectric ceramics are the most promising materials. Antiferroelectric has high storage density compared to linear dielectric, and ferroelectric ceramics. It is because of low Pr, large Pmax, and corresponding high dielectric breakdown strength (DBS) [7, 8]. However, most of
the
antiferroelectric
materials
are
made
of
Pb-based
such
as
(Pb0.98La0.02)(Zr0.55Sn0.45)0.995O3 [9], Pb0.97La0.02(Zr0.58Sn0.335Ti0.085)O3 [10], La modified Pb(Lu1/2Nb1/2)O3 [11], etc. The European Commission has made legislation to restrict the use of Pb-based materials. Because, it has affected the serious human health, and environmental problems [12]. In order to this, there is a requirement of new antiferroelectric for high energy density, and environment-friendly ceramic materials. There are many Pb-free materials with (Bi0.5Na0.5)TiO3 (BNT), (K0.5Na0.5)NbO3 (KNN), and BaTiO3 (BT)-based such as Na0.5Bi0.5TiO3-BaTiO3 [13], (Na0.5Bi0.5)TiO3BaTiO3-K0.5Na0.5NbO3
[14],
and
Na0.5Bi0.5TiO3-BaTiO3-BiFeO3
[15],
BaTiO3-
Bi(Mg2/3Nb2/3)O3 [4], K0.5Na0.5NbO3-SrTiO3 [16], Na0.5Bi0.5TiO3-BaSnO3 [17], etc. The main reason with BNT-based materials are Bi(6s2) lone pair like Pb(6s2) [18]. To improve the energy storage density, many substituents/dopants has been carried out. Gao et al. examined 0.89BNT-0.06BT-0.05KNN ceramic, and obtained a recoverable energy density (Wrec) ~ 0.59 J/cm3 at 56 kV/cm applied field [19]. Li et al. explored the 0.88BT0.12Bi(Li0.5Nb0.5)O3 system, and obtained Wrec ~ 2.03 J/cm3 at 270 kV/cm [20]. Ma et al. 2
synthesized BNT-ST-5AN, and achieved Wrec ~ 2.03 J/cm3 at 120 kV/cm applied field [21]. Like these, several compounds are synthesized to succeed the large Wrec and η. In the present study, Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 (for x = 0, 0.03, 0.06, 0.09, 0.12, and 0.15) ceramics are investigated with structure, dielectric, fatigue resistant, and energy density in detail. Composition for x = 0.03, a high Wrec and fatigue-free properties are obtained. Hence, composition x = 0.03 might be applicable for high energy density devices. In addition, this study would offer the best way to find the high Wrec in lead-free BNT-based ceramics for pulsed power capacitors. 2. Experiments Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 (NBBLZTS-x, for x = 0, 0.03, 0.06, 0.09, 0.12, and 0.15) ceramics were synthesized via the solid-state reaction technique. Reagents Na2CO3 (99.9 %), Bi2O3 (99.9 %), ZrO2 (99.9 %), BaCO3 (99.9 %), TiO2 (99.9 %), La2O3 (99.9 %), and SnO2 (99.9 %) were taken as raw materials. Dried reagents were taken in their stoichiometric ratio, and milled with zirconia balls in an alcoholic medium at 350 revolutions per minute (rpm) for 12 h. Slurries were dried, sieved, and heated at 850 °C for 2 h. Heated powders were again ball-milled in the same medium for 12 h to make the uniform, and fined powders. Re-ball milled powders were dried and sieved using a 60-mesh grid. These powders were pressed in the form of pellets via the die set at 80 MPa first, after that 250 MPa by the cold isostatic pressing device. These pressed pellets were sintered at 1175 °C for 2.3 h to form the ceramics. Throughout heating, the pellets were covered with the same composition samples to reduce the volatility of the Na/Bi elements at such high temperatures. These ceramics were polished to reduce the thickness, and uniformity in the samples. The silver paste was painted on both sides of pellets and cured at 550 °C for 30 min. These pellets were used for the electrical characterizations. The phase and structure for NBBLZTS-x ceramics were determined using X-ray diffraction (XRD; D/Max-RB, Rigaku, Tokyo, Japan) with Cu Kα (λ = 1.5406 Å) radiation. The measurement was done using the Bragg angle (2θ) ranging from 15 to 90° with 1°/min scan rate. Raman spectra were collected with a 532 nm argon-ion laser excitation (Horiba Jobin-Yvon, Lyon, France) of the polished pellets. The surface microstructure was observed with a scanning electron microscope (SEM; JSM EMP800, 3
JEOL, Tokyo, Japan). Ferroelectric measurement was performed using a ferroelectric analyzer (TF-2000, Aix ACCT, Aachen, Germany). Temperature-dependent dielectric response was measured with a precision impedance analyzer (4294A, Agilent, Santa, CA, USA). Impedance data were collected with an impedance analyzer (Solartron, SI 1260, Hampshire, U.K.).
3. Results and discussion 3.1 Microstructure analysis Crystal structure and phase purity of NBBLZTS-x ceramics are analyzed using XRD patterns at ambient conditions, as displayed in Fig. 1. These samples are presented perovskite structure, and there are impurity peaks for x ≥ 0.06 compositions as denoted using the star marks (Fig. 1a). Therefore, the solubility of Sn in NBBLZTS-x ceramics is x ≤ 0.03. To visualize the effect of substitution on peak shape and positions, some XRD peaks 39 - 41°, and 45 – 48° range are zoomed as displayed in Fig. 1(b-c), respectively. There is a clear shift of Bragg positions towards the low angle with increasing dopant as indicated using the dotted line. This indicates the lattice expansion with increasing composition. The shift of peak might be related to the higher ionic radii of Sn (0.69 Å, VI) compared to Ti (0.605 A, VI) [22]. Also, there is no splitting in (200), and (111) Bragg peaks with increasing composition as presented in Fig. 1(b-c). Hence, it indicates the pseudo-cubic type behavior of the samples. Similar type pseudo-cubic structures are reported in the literature [23, 24]. To explore further, Raman measurement was carried out on the polished NBBLZTS-x ceramics in 80-1000 cm-1 range at the ambient conditions, as presented in Fig 2. The obtained modes of Raman spectra are analogous to the reported in the literature earlier with BNT-based ceramics [25, 26]. As a representative, NBBLZTS-0 sample is fitted with the corresponding peaks using the Lorentzian function as shown by the dotted line for sum, and convoluted peaks (Fig. 2). Mainly, it is covered the four regions of vibrations: the vibrations lower than 200 cm-1 is assigned, the vibration for the A-site ions such as Na/Bi/Ba/La. There is a decrease in intensity with increasing composition. The second region is defined as B-site with oxygen in perovskite ABO3 4
lattice to a range from 200 to 400 cm-1. In NBBLZTS-x ceramics, it is related to the vibration of Ti/Zr/Sn with oxygens. In the third region, the vibrations of 450-700 cm-1 range is recognized for the TiO6 octahedron. It is revealed that these modes (double peaks) widen with a slight redshift as a function of composition. It confirms, the structural change in the NBBLZTS-x ceramics. In the fourth region, the vibration range more than 700 cm-1 is associated with the superposition of the modes [27, 28]. Surface morphology for sintered NBBLZTS-x ceramics using SEM is presented in Fig. 3(a-f). The obtained images have perceived well dense and compact for all ceramics. There is no significant variation in the average grain size. It is found to slightly enhance from 1.4 ± 0.6 µm (NBBLZTS-0) to 1.6 ± 0.5 µm (NBBLZTS-0.15) with increasing composition. The relative density for NBBLZTS-x ceramics is estimated as 94 %, 95 %, 94 %, 93 %, 94 %, and 95 %, respectively. 3.2 Dielectric behaviors To investigate the dielectric properties of NBBLZTS-x ceramics, dielectric permittivity (ε'), and loss tangent (tanδ) versus temperature are measured with some fixed frequencies as presented in Fig. 4(a-f). There are two dielectric anomalies obtained in ε' versus temperature plots. Anomaly at low temperature is ascribed to temperature evolution of tetragonal P4bm, and rhombohedral R3c polar nano regions (PNRs) with obvious frequency dispersion [29-31]. The first anomaly is denoted as Ts in Fig. 4a. Anomaly at high temperature is represented as Tm. It is related to the transition of PNRs with R3c to P4bm phase [5]. Discrete relaxor natures, containing frequency variations, and wide ferroelectric to paraelectric transition peak, are recognized in NBBLZTS-x samples. It is revealed, the reduction in long-range ferroelectric order, and distortion local lattice with increasing composition. Also, the Ts shift gradually towards room temperature with the increasing dopant. In addition, maximum permittivity (ε'm) is found to gradually reduce with composition, which might be due to charge fluctuation, and site disorder [32, 33]. 3.3 Ferroelectric studies P-E and J-E curves are presented in Fig. 5(a-f) at 1 Hz frequency. The sample NBBLZTS-0 has displayed the double pinched type ferroelectric. In addition, the J-E curve has shown the two corresponding peaks. This type of nature in BNT-based 5
ceramics is found due to the ferroelectric (rhombohedral: R3c), and antiferroelectric (tetragonal: P4bm) contribution. With increasing composition, the P-E curve becomes slimmer compared to NBBLZTS-0 composition. It indicates that P4bm phase increases and the sample tends towards the relaxor type with increasing composition. Also, the J-E curve has represented relaxor type behavior. It denotes that increasing composition, the P-E and J-E behaviors designate the relaxor nature. Similar type BNT-based ceramics are reported in the literature [34, 35]. Estimated Pmax, Pr, and difference of Pmax - Pr are presented in Fig. 6a at room temperature. Pr and Pmax are revealed to decrease with composition. The decrease of Pr and Pmax might be related to the relaxor nature of the samples. The difference between Pmax and Pr is obtained to increase for NBBLZTS-0.03, then after the decrease with increasing composition. Increase the value Pmax - Pr for NBBLZTS-0.03 composition would be supported to enhance Wrec of the ceramic. W and Wrec for NBBLZTS-x ceramics are calculated with the P-E curves (Fig. 6b) using equations below [36, 37]: W
=
W=W η=
E dP
(1)
+W
(2)
× 100 %
(3)
Where Wrec, Pr, Pmax, E, W, and η are described as recoverable energy density, remnant polarization, maximum polarization, applied electric field, total supplied energy density, and conversion efficiency respectively. Total supplied energy density (W) is obtained to decrease with composition as shown in Fig. 6b. Wrec is revealed to increase for NBBLZTS-0.03, then after decrease as a function of composition. The estimated conversion efficiency (η) is high for NBBLZTS-0.03 composition compared to others. Hence, the ceramic NBBLZTS-0.03 is recognized attention for further study in detail. Fig. 7a represents the P-E diagram at different E for NBBLZTS-0.03 ceramic. It is revealed that Pmax increases rapidly, while Pr slightly with E. The increase of Pmax is a favorable condition for high Wrec. Estimated W, Wrec, and η with increasing applied E are plotted in Fig. 7b. Both Wrec, and W are found to increase with E. The maximum Wrec ~ 1.58 J/cm3 with η ~ 71.7 % is found at 110 kV/cm field. High Wrec is obtained due to the
6
high Pmax and E. A comparison of other BNT-based materials is carried out in Table 1 with the NBBLZTS-0.03 sample.
Table 1. Comparison of other BNT-based ceramics with NBBLZTS-0.03 composition.
Compositions
Wrec (J/cm3)
η%
E (kV/cm)
Refs.
BNT – BT- NBN
1.4
66.3
142
[38]
BNKSTT-5Li
1.83
67
120
[39]
BNYT30
1.215
68.7
98
[40]
NBT-6KS
0.57
53.2
90
[41]
NBST-La
1.2
78
90
[42]
BNKT-0.08AN
1.41
-
105
[43]
BNTBT - SZ-NN
0.95
66
110
[44]
BNT-BCTZ
0.87
82.37
93.5
[45]
BNT - BST-1NN
1.03
85.8
85
[46]
BNT - BKT-6BA
1.15
73.2
105
[47]
NBBLZTS-0.03
1.27
69.7
100
This work
NBBLZTS-0.03
1.58
71.7
110
This work
Temperature-dependent W, Wrec, and η for NBBLZTS-0.03 ceramic at 100 kV/cm field are displayed in Fig. 8(a-b). P-E curves are represented the slight decrease of Pmax, and a significant reduction in Pr value with increasing temperature. Also, P-E curves become slimmer with increasing temperature. It would help to increase Wrec, η, and decrease the value of W. Wrec, and η are found to increase while W reduce with temperature as displayed in Fig. 8b. The highest Wrec ~ 1.53 J/cm3 with η ~ 88.6 % is obtained at 110 °C. Whereas, Wrec ~ 1.51 J/cm3 with η ~ 88.1 % are estimated at 120 °C with a slight decrease from 110 °C. Hence, NBBLZTS-0.03 ceramic is useable from 30 120 °C range for the energy storage applications.
7
3.4 Fatigue resistant To check the reliability of NBBLZTS-0.03 ceramic material for long term application, fatigue test is performed from 1 to 105 cycles at ambient condition. The representative P-E curves with different cycles at 100 kV/cm are plotted in Fig. 9a. There is no significant variation in P-E curves from 1 to 105 cycles. In addition, to see the parameters such as Pr, and Pmax are almost constant with cycles. Also, Wrec is calculated with cycles, and plotted in Fig. 9b. There is almost no change in Wrec with cycles. Hence, NBBLZTS-0.03 ceramic is fatigue-free from 1 to 105 cycles. Therefore, this material is useable for long term energy storage devices. 3.5 Conduction mechanism To understand the conduction, and relaxation mechanism in NBBLZTS-x ceramics, the impedance technique is carried out. Impedance Z is recognized to model AC impedance. Generally, a series of parallel resistance-capacitance (R-C circuits) are modeled for grain contribution, grain boundary, and electrode effect [48]. The impedance spectra for NBBLZTS-x ceramics are presented in Fig. 10a at 700 °C for all the samples. The Nyquist plots (-Z'' versus Z') are showed only one semicircle for all ceramics, and passing through the origin. Hence, the samples have only grain contribution. The resistance is estimated to decrease for NBBLZTS-x ≤ 0.06 samples, and start to increase for NBBLZTS-x ≥ 0.09 compositions. The increase of resistance might be related to impurity in the ceramics. Temperature-dependent impedance spectra for NBBLZTS-0, and NBBLZTS-0.03 ceramics are displayed, respectively in Fig. 10(b-c). The resistance is observed to decrease with increasing temperature as the nature of ceramics. Conductivity versus temperature plots are represented in Fig. 10d for all ceramics. Plots of ln(σ) with 1000/T are showed the linear for all the samples. This conductivity versus temperature plots are modeled by the Arrhenius equation as below [49]: =
exp (
!
" #
)
(4)
Where T, k, Ea, and σo are known as absolute temperature, Boltzmann constant, activation energy, and pre-exponential factor, respectively. Calculated Ea values are from ~ 1.71 eV to ~ 1.99 eV range as shown in Fig. 10d. The range of Ea corresponds to the oxygen vacancies, hence, defects are mainly related to the oxygen vacancies [50].
8
4. Conclusion Lead-free Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 (for x = 0, 0.03, 0.06, 0.09, 0.12, and 0.15) systems were prepared by conventional solid-state technique. Pseudocubic behavior of the samples was confirmed by the XRD. Also, the higher modified samples (NBBLZTS-x ≥ 0.06) were presented the secondary phase. Surface microstructure was ascribed the compact ceramics with increasing the average grain size. Electric-field induced polarization was revealed slim type hysteresis loops with compositions. The sample NBBLZTS-0.03 was presented the maximum difference between Pmax - Pr compared to others. For NBBLZTS-0.03 ceramic, the calculated Wrec ~ 1.58 J/cm3 with η ~ 71.7 % at E ~ 110 kV/cm are obtained. Also, temperature-dependent study of NBBLZTS-0.03 ceramic was revealed a high η ~ 88.6 % with Wrec ~ 1.53 J/cm3 at 110 °C for 100 kV/cm applied field. In addition, NBBLZTS-0.03 ceramic was presented the fatigue-free behavior from 1 to 105 cycles. Hence, NBBLZTS-0.03 ceramic might be applicable for large Wrec at ambient and wide temperature range.
Acknowledgements This work has been supported by the National Nature Science Foundation (51672220), the National Defense Science Foundation (32102060303), the Fundamental Research Funds for the Central Universities of NPU (3102019GHXM002), the SKLSP Project (2019-TZ-04), and the Open-end Fund of International Joint Research Laboratory of Henan Province for Underground Space Development and Disaster Prevention, Henan Polytechnic University, China. We would also like to thank the Analytical & Testing Center of Northwestern Polytechnical University for SEM, TEM, AFM, Raman and XRD test.
9
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[21] W. Ma, Y. Zhu, M.A. Marwat, P. Fan, B. Xie, D. Salamon, Z.-G. Ye, H. Zhang, Enhanced energy-storage performance with excellent stability under low electric fields in BNT–ST relaxor ferroelectric ceramics, J. Mater. Chem. C, 7 (2019) 281-288. [22] R.D. Shannon, Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides, Acta Crystallogr., Sect. A, 32 (1976) 751-767. [23] C. Wang, Q. Li, A.K. Yadav, H. Peng, H. Fan, Bi0.48(Na0.84K0.16)0.48Sr0.04(Ti1-xTax)O3 lead-free ceramics with enhanced electric field-induced strain, J. Alloys Compd., 803 (2019) 1082-1089. [24] Q. Wei, M. Zhu, M. Zheng, Y. Hou, Sr(Zn1/3Nb2/3)O3-induced R3c to P4bm transition and large field-induced strain in 0.80(Bi0.5Na0.5)TiO3–0.20SrTiO3 ceramics, J. Mater. Res., 34 (2019) 1210-1218. [25] B. Wylie-van Eerd, D. Damjanovic, N. Klein, N. Setter, J. Trodahl, Structural complexity of (Na0.5Bi0.5) TiO3-BaTiO3 as revealed by Raman spectroscopy, Phys. Rev. B, 82 (2010) 104112. [26] J. Sui, H. Fan, H. Peng, J. Ma, A.K. Yadav, W. Chao, M. Zhang, G. Dong, Enhanced energy-storage performance and temperature-stable dielectric properties of (1x)[(Na0.5Bi0.5)0.95Ba0.05]0.98La0.02TiO3-xK0.5Na0.5NbO3 lead-free ceramics, Ceram. Int., 45 (2019) 20427-20434. [27] W. Bai, P. Li, L. Li, J. Zhang, B. Shen, J. Zhai, Structure evolution and large strain response in BNT–BT lead-free piezoceramics modified with Bi(Ni0.5Ti0.5)O3, J. Alloys Compd., 649 (2015) 772-781. [28] E. Aksel, J.S. Forrester, H.M. Foronda, R. Dittmer, D. Damjanovic, J.L. Jones, Structure and properties of La-modified Na0.5Bi0.5TiO3 at ambient and elevated temperatures, J. Appl. Phys., 112 (2012) 054111. [29] Q. Wei, M. Zhu, M. Zheng, Y. Hou, J. Li, Y. Bai, Large electrocaloric effect near room temperature in lead–free Bi0.5Na0.5TiO3-based ergodic relaxor observed by differential scanning calorimetry, Scr. Mater., 171 (2019) 10-15. [30] P. Butnoi, S. Manotham, P. Jaita, C. Randorn, G. Rujijanagul, High thermal stability of energy storage density and large strain improvement of lead-free Bi0.5(Na0.40K0.10)TiO3 piezoelectric ceramics doped with La and Zr, J. Eur. Ceram. Soc., 38 (2018) 3822-3832.
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[31] H. Yang, F. Yan, Y. Lin, T. Wang, Enhanced energy-storage properties of lanthanum-doped Bi0.5Na0.5TiO3-based lead-free ceramics, Energy Technology, 6 (2018) 357-365. [32] R. Dittmer, E.-M. Anton, W. Jo, H. Simons, J.E. Daniels, M. Hoffman, J. Pokorny, I.M. Reaney, J. Rödel, A high-temperature-capacitor dielectric based on K0.5Na0.5NbO3modified Bi1/2Na1/2TiO3–Bi1/2K1/2TiO3, J. Am. Ceram. Soc., 95 (2012) 3519-3524. [33] A. Singh, R. Chatterjee, Structural, electrical, and strain properties of stoichiometric 1−x−y(Bi0.5Na0.5)TiO3−x(Bi0.5K0.5TiO3)−y(Na0.5K0.5)NbO3 solid solutions, J. Appl. Phys., 109 (2011) 024105. [34] H.-S. Han, W. Jo, J.-K. Kang, C.-W. Ahn, I. Won Kim, K.-K. Ahn, J.-S. Lee, Incipient piezoelectrics and electrostriction behavior in Sn-doped Bi1/2(Na0.82K0.18)1/2TiO3 lead-free ceramics, J. Appl. Phys., 113 (2013) 154102. [35] S.K. Ghosh, S. Saha, T.P. Sinha, S.K. Rout, Large electrostrictive effect in (Ba1xGd2x/3)Zr0.3Ti0.7O3
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14
Figure captions
Fig. 1. XRD patterns of NBBLZTS-x ceramics in the 2θ range of (a) 15 - 90°, (b) 39 - 40° and (c) 45 - 48°. Fig. 2. Raman spectrum for NBBLZTS-x ceramics at room temperature. NBBLZTS-0 sample is fitted using the Lorentzian function, presented using the dotted curves. Fig. 3. FESEM microstructure for NBBLZTS-x where (a) NBBLZTS-0, (b) NBBLZTS0.03, (c) NBBLZTS-0.06, (d) NBBLZTS-0.09, (e) NBBLZTS-0.12, and (f) NBBLZTS-0.15 ceramics. Fig. 4. ε' and tanδ versus temperature for NBBLZTS-x, where (a) NBBLZTS-0, (b) NBBLZTS-0.03, (c) NBBLZTS-0.06, (d) NBBLZTS-0.09, (e) NBBLZTS-0.12, and (f) NBBLZTS-0.15 compositions. Fig. 5. P-E and J-E curves for NBBLZTS-x, where (a) NBBLZTS-0, (b) NBBLZTS-0.03, (c) NBBLZTS-0.06, (d) NBBLZTS-0.09, (e) NBBLZTS-0.12, and (f) NBBLZTS-0.15 compositions. Fig. 6. (a) Calculated remnant polarization (Pr), maximum polarization (Pmax), and Pmax Pr with composition. (b) Storage density (Wrec), total supplied density (W), and η with compositions. Fig. 7. (a) Electric field (E) dependent polarization (P) for NBBLZTS-0.03 ceramic and (b) Calculated Wrec, W, and η at different applied field. Fig. 8. (a) P-E curves at different temperatures from 30 to 120 °C for NBBLZTS-0.03 ceramic, and (b) estimated Wrec, W, and η various temperature. Fig. 9. (a) Fatigue test of P-E curves from 1-105 cycles, and (b) calculated Pr, Pmax, and Wrec with cycles. Fig. 10. (a) AC impedance spectra for NBBLZTS-x at 700 °C, (b-c) impedance plots for NBBLZTS-0 and NBBLZTS-0.03 samples at different temperature, respectively, (d) estimated activation energy for NBBLZTS-x ceramics.
15
The author confirms, there is no conflict of interest exists in the submission of this manuscript, and the manuscript is approved by all authors for publication. I would like to declare on behalf of my co-authors that the work described was original research that has not been published previously, and not under consideration for publication elsewhere, in whole or in part. All the authors listed have approved the manuscript that is enclosed.
S0272-8842(19)33193-1
DOI:
https://doi.org/10.1016/j.ceramint.2019.11.015
Reference:
CERI 23384
To appear in:
Ceramics International
Received Date: 29 October 2019 Revised Date:
1 November 2019
Accepted Date: 3 November 2019
Please cite this article as: A.K. Yadav, H. Fan, B. Yan, C. Wang, M. Zhang, J. Ma, W. Wang, W. Dong, S. Wang, High energy storage density and stable fatigue resistance of Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 ceramics, Ceramics International (2019), doi: https:// doi.org/10.1016/j.ceramint.2019.11.015. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier Ltd.
High Energy Storage Density and Stable Fatigue Resistance of Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 Ceramics Arun Kumar Yadav a, Huiqing Fan a, b, c *, Benben Yan a, Chao Wang a, Mingching Zhanga, Jiangwei Maa, Weijia Wang a, Wenqiang Dong b, Shuren Wang c a
State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, China
b
Institute of Culture and Heritage, Northwestern Polytechnical University, Xi'an 710072, China c
International Joint Research Laboratory of Henan Province for Underground Space
Development and Disaster Prevention, Henan Polytechnic University, Jiaozuo 454001, China *Corresponding author: [email protected], [email protected] Abstract Energy density and fatigue resistance properties were investigated for lead-free Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 (for 0 ≤ x ≤ 0.15) ceramics, synthesized via solid-state reaction technique. Perovskite pseudo-cubic crystal structure was revealed for all ceramics using X-ray diffraction. Polarization and current density versus electric field were perceived and suggested the relaxor behavior with increasing composition. A high storage energy density ~1.58 J/cm3, and conversion efficiency ~71.7 % at ~110 kV/cm applied field was obtained for x = 0.03 composition at room temperature. Energy storage density was revealed ~ 1.53 J/cm3, and efficiency ~ 88.6 % at 110 °C with a 100 kV/cm applied field. In addition, ceramic x = 0.03 was fatigue-free from 1 to 105 cycles. Hence, the composition x = 0.03 might be applicable for high energy storage devices.
Keywords: Perovskite; Lead-free ceramics; Relaxor ferroelectrics; Energy storage properties; Fatigue resistant 1. Introduction With increasing the capacitor’s demand in the area of pulsed power applications, particularly dielectric capacitors with large storage density purposes have been 1
investigated widely, and explored for important functions [1, 2]. Dielectric ceramics have many advantages such as rapid charge-discharge rate, high mechanical strength, and temperature properties, etc. Also, it has one significant drawback of low energy storage density compared to other known energy storage systems like batteries and fuel cells, etc. Currently, high storage density and large thermal range stability for dielectric capacitor materials have attracted considerable attention. Dielectric ceramics for energy density are especially four types such as ferroelectrics, linear dielectrics, relaxor ferroelectrics, and antiferroelectrics [3, 4]. Linear dielectric has high storage efficiency but low energy density. Ferroelectric is known for large remnant polarization (Pr) and high hysteresis loss. Antiferroelectric and relaxor materials are recognized for large storage energy density and conversion efficiency (η) [5]. To plan for large storage density dielectric capacitors required low remnant polarization, large maximum polarization (Pmax), and high dielectric breakdown strength, etc. [6]. Seeing these necessities, antiferroelectric ceramics are the most promising materials. Antiferroelectric has high storage density compared to linear dielectric, and ferroelectric ceramics. It is because of low Pr, large Pmax, and corresponding high dielectric breakdown strength (DBS) [7, 8]. However, most of
the
antiferroelectric
materials
are
made
of
Pb-based
such
as
(Pb0.98La0.02)(Zr0.55Sn0.45)0.995O3 [9], Pb0.97La0.02(Zr0.58Sn0.335Ti0.085)O3 [10], La modified Pb(Lu1/2Nb1/2)O3 [11], etc. The European Commission has made legislation to restrict the use of Pb-based materials. Because, it has affected the serious human health, and environmental problems [12]. In order to this, there is a requirement of new antiferroelectric for high energy density, and environment-friendly ceramic materials. There are many Pb-free materials with (Bi0.5Na0.5)TiO3 (BNT), (K0.5Na0.5)NbO3 (KNN), and BaTiO3 (BT)-based such as Na0.5Bi0.5TiO3-BaTiO3 [13], (Na0.5Bi0.5)TiO3BaTiO3-K0.5Na0.5NbO3
[14],
and
Na0.5Bi0.5TiO3-BaTiO3-BiFeO3
[15],
BaTiO3-
Bi(Mg2/3Nb2/3)O3 [4], K0.5Na0.5NbO3-SrTiO3 [16], Na0.5Bi0.5TiO3-BaSnO3 [17], etc. The main reason with BNT-based materials are Bi(6s2) lone pair like Pb(6s2) [18]. To improve the energy storage density, many substituents/dopants has been carried out. Gao et al. examined 0.89BNT-0.06BT-0.05KNN ceramic, and obtained a recoverable energy density (Wrec) ~ 0.59 J/cm3 at 56 kV/cm applied field [19]. Li et al. explored the 0.88BT0.12Bi(Li0.5Nb0.5)O3 system, and obtained Wrec ~ 2.03 J/cm3 at 270 kV/cm [20]. Ma et al. 2
synthesized BNT-ST-5AN, and achieved Wrec ~ 2.03 J/cm3 at 120 kV/cm applied field [21]. Like these, several compounds are synthesized to succeed the large Wrec and η. In the present study, Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 (for x = 0, 0.03, 0.06, 0.09, 0.12, and 0.15) ceramics are investigated with structure, dielectric, fatigue resistant, and energy density in detail. Composition for x = 0.03, a high Wrec and fatigue-free properties are obtained. Hence, composition x = 0.03 might be applicable for high energy density devices. In addition, this study would offer the best way to find the high Wrec in lead-free BNT-based ceramics for pulsed power capacitors. 2. Experiments Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 (NBBLZTS-x, for x = 0, 0.03, 0.06, 0.09, 0.12, and 0.15) ceramics were synthesized via the solid-state reaction technique. Reagents Na2CO3 (99.9 %), Bi2O3 (99.9 %), ZrO2 (99.9 %), BaCO3 (99.9 %), TiO2 (99.9 %), La2O3 (99.9 %), and SnO2 (99.9 %) were taken as raw materials. Dried reagents were taken in their stoichiometric ratio, and milled with zirconia balls in an alcoholic medium at 350 revolutions per minute (rpm) for 12 h. Slurries were dried, sieved, and heated at 850 °C for 2 h. Heated powders were again ball-milled in the same medium for 12 h to make the uniform, and fined powders. Re-ball milled powders were dried and sieved using a 60-mesh grid. These powders were pressed in the form of pellets via the die set at 80 MPa first, after that 250 MPa by the cold isostatic pressing device. These pressed pellets were sintered at 1175 °C for 2.3 h to form the ceramics. Throughout heating, the pellets were covered with the same composition samples to reduce the volatility of the Na/Bi elements at such high temperatures. These ceramics were polished to reduce the thickness, and uniformity in the samples. The silver paste was painted on both sides of pellets and cured at 550 °C for 30 min. These pellets were used for the electrical characterizations. The phase and structure for NBBLZTS-x ceramics were determined using X-ray diffraction (XRD; D/Max-RB, Rigaku, Tokyo, Japan) with Cu Kα (λ = 1.5406 Å) radiation. The measurement was done using the Bragg angle (2θ) ranging from 15 to 90° with 1°/min scan rate. Raman spectra were collected with a 532 nm argon-ion laser excitation (Horiba Jobin-Yvon, Lyon, France) of the polished pellets. The surface microstructure was observed with a scanning electron microscope (SEM; JSM EMP800, 3
JEOL, Tokyo, Japan). Ferroelectric measurement was performed using a ferroelectric analyzer (TF-2000, Aix ACCT, Aachen, Germany). Temperature-dependent dielectric response was measured with a precision impedance analyzer (4294A, Agilent, Santa, CA, USA). Impedance data were collected with an impedance analyzer (Solartron, SI 1260, Hampshire, U.K.).
3. Results and discussion 3.1 Microstructure analysis Crystal structure and phase purity of NBBLZTS-x ceramics are analyzed using XRD patterns at ambient conditions, as displayed in Fig. 1. These samples are presented perovskite structure, and there are impurity peaks for x ≥ 0.06 compositions as denoted using the star marks (Fig. 1a). Therefore, the solubility of Sn in NBBLZTS-x ceramics is x ≤ 0.03. To visualize the effect of substitution on peak shape and positions, some XRD peaks 39 - 41°, and 45 – 48° range are zoomed as displayed in Fig. 1(b-c), respectively. There is a clear shift of Bragg positions towards the low angle with increasing dopant as indicated using the dotted line. This indicates the lattice expansion with increasing composition. The shift of peak might be related to the higher ionic radii of Sn (0.69 Å, VI) compared to Ti (0.605 A, VI) [22]. Also, there is no splitting in (200), and (111) Bragg peaks with increasing composition as presented in Fig. 1(b-c). Hence, it indicates the pseudo-cubic type behavior of the samples. Similar type pseudo-cubic structures are reported in the literature [23, 24]. To explore further, Raman measurement was carried out on the polished NBBLZTS-x ceramics in 80-1000 cm-1 range at the ambient conditions, as presented in Fig 2. The obtained modes of Raman spectra are analogous to the reported in the literature earlier with BNT-based ceramics [25, 26]. As a representative, NBBLZTS-0 sample is fitted with the corresponding peaks using the Lorentzian function as shown by the dotted line for sum, and convoluted peaks (Fig. 2). Mainly, it is covered the four regions of vibrations: the vibrations lower than 200 cm-1 is assigned, the vibration for the A-site ions such as Na/Bi/Ba/La. There is a decrease in intensity with increasing composition. The second region is defined as B-site with oxygen in perovskite ABO3 4
lattice to a range from 200 to 400 cm-1. In NBBLZTS-x ceramics, it is related to the vibration of Ti/Zr/Sn with oxygens. In the third region, the vibrations of 450-700 cm-1 range is recognized for the TiO6 octahedron. It is revealed that these modes (double peaks) widen with a slight redshift as a function of composition. It confirms, the structural change in the NBBLZTS-x ceramics. In the fourth region, the vibration range more than 700 cm-1 is associated with the superposition of the modes [27, 28]. Surface morphology for sintered NBBLZTS-x ceramics using SEM is presented in Fig. 3(a-f). The obtained images have perceived well dense and compact for all ceramics. There is no significant variation in the average grain size. It is found to slightly enhance from 1.4 ± 0.6 µm (NBBLZTS-0) to 1.6 ± 0.5 µm (NBBLZTS-0.15) with increasing composition. The relative density for NBBLZTS-x ceramics is estimated as 94 %, 95 %, 94 %, 93 %, 94 %, and 95 %, respectively. 3.2 Dielectric behaviors To investigate the dielectric properties of NBBLZTS-x ceramics, dielectric permittivity (ε'), and loss tangent (tanδ) versus temperature are measured with some fixed frequencies as presented in Fig. 4(a-f). There are two dielectric anomalies obtained in ε' versus temperature plots. Anomaly at low temperature is ascribed to temperature evolution of tetragonal P4bm, and rhombohedral R3c polar nano regions (PNRs) with obvious frequency dispersion [29-31]. The first anomaly is denoted as Ts in Fig. 4a. Anomaly at high temperature is represented as Tm. It is related to the transition of PNRs with R3c to P4bm phase [5]. Discrete relaxor natures, containing frequency variations, and wide ferroelectric to paraelectric transition peak, are recognized in NBBLZTS-x samples. It is revealed, the reduction in long-range ferroelectric order, and distortion local lattice with increasing composition. Also, the Ts shift gradually towards room temperature with the increasing dopant. In addition, maximum permittivity (ε'm) is found to gradually reduce with composition, which might be due to charge fluctuation, and site disorder [32, 33]. 3.3 Ferroelectric studies P-E and J-E curves are presented in Fig. 5(a-f) at 1 Hz frequency. The sample NBBLZTS-0 has displayed the double pinched type ferroelectric. In addition, the J-E curve has shown the two corresponding peaks. This type of nature in BNT-based 5
ceramics is found due to the ferroelectric (rhombohedral: R3c), and antiferroelectric (tetragonal: P4bm) contribution. With increasing composition, the P-E curve becomes slimmer compared to NBBLZTS-0 composition. It indicates that P4bm phase increases and the sample tends towards the relaxor type with increasing composition. Also, the J-E curve has represented relaxor type behavior. It denotes that increasing composition, the P-E and J-E behaviors designate the relaxor nature. Similar type BNT-based ceramics are reported in the literature [34, 35]. Estimated Pmax, Pr, and difference of Pmax - Pr are presented in Fig. 6a at room temperature. Pr and Pmax are revealed to decrease with composition. The decrease of Pr and Pmax might be related to the relaxor nature of the samples. The difference between Pmax and Pr is obtained to increase for NBBLZTS-0.03, then after the decrease with increasing composition. Increase the value Pmax - Pr for NBBLZTS-0.03 composition would be supported to enhance Wrec of the ceramic. W and Wrec for NBBLZTS-x ceramics are calculated with the P-E curves (Fig. 6b) using equations below [36, 37]: W
=
W=W η=
E dP
(1)
+W
(2)
× 100 %
(3)
Where Wrec, Pr, Pmax, E, W, and η are described as recoverable energy density, remnant polarization, maximum polarization, applied electric field, total supplied energy density, and conversion efficiency respectively. Total supplied energy density (W) is obtained to decrease with composition as shown in Fig. 6b. Wrec is revealed to increase for NBBLZTS-0.03, then after decrease as a function of composition. The estimated conversion efficiency (η) is high for NBBLZTS-0.03 composition compared to others. Hence, the ceramic NBBLZTS-0.03 is recognized attention for further study in detail. Fig. 7a represents the P-E diagram at different E for NBBLZTS-0.03 ceramic. It is revealed that Pmax increases rapidly, while Pr slightly with E. The increase of Pmax is a favorable condition for high Wrec. Estimated W, Wrec, and η with increasing applied E are plotted in Fig. 7b. Both Wrec, and W are found to increase with E. The maximum Wrec ~ 1.58 J/cm3 with η ~ 71.7 % is found at 110 kV/cm field. High Wrec is obtained due to the
6
high Pmax and E. A comparison of other BNT-based materials is carried out in Table 1 with the NBBLZTS-0.03 sample.
Table 1. Comparison of other BNT-based ceramics with NBBLZTS-0.03 composition.
Compositions
Wrec (J/cm3)
η%
E (kV/cm)
Refs.
BNT – BT- NBN
1.4
66.3
142
[38]
BNKSTT-5Li
1.83
67
120
[39]
BNYT30
1.215
68.7
98
[40]
NBT-6KS
0.57
53.2
90
[41]
NBST-La
1.2
78
90
[42]
BNKT-0.08AN
1.41
-
105
[43]
BNTBT - SZ-NN
0.95
66
110
[44]
BNT-BCTZ
0.87
82.37
93.5
[45]
BNT - BST-1NN
1.03
85.8
85
[46]
BNT - BKT-6BA
1.15
73.2
105
[47]
NBBLZTS-0.03
1.27
69.7
100
This work
NBBLZTS-0.03
1.58
71.7
110
This work
Temperature-dependent W, Wrec, and η for NBBLZTS-0.03 ceramic at 100 kV/cm field are displayed in Fig. 8(a-b). P-E curves are represented the slight decrease of Pmax, and a significant reduction in Pr value with increasing temperature. Also, P-E curves become slimmer with increasing temperature. It would help to increase Wrec, η, and decrease the value of W. Wrec, and η are found to increase while W reduce with temperature as displayed in Fig. 8b. The highest Wrec ~ 1.53 J/cm3 with η ~ 88.6 % is obtained at 110 °C. Whereas, Wrec ~ 1.51 J/cm3 with η ~ 88.1 % are estimated at 120 °C with a slight decrease from 110 °C. Hence, NBBLZTS-0.03 ceramic is useable from 30 120 °C range for the energy storage applications.
7
3.4 Fatigue resistant To check the reliability of NBBLZTS-0.03 ceramic material for long term application, fatigue test is performed from 1 to 105 cycles at ambient condition. The representative P-E curves with different cycles at 100 kV/cm are plotted in Fig. 9a. There is no significant variation in P-E curves from 1 to 105 cycles. In addition, to see the parameters such as Pr, and Pmax are almost constant with cycles. Also, Wrec is calculated with cycles, and plotted in Fig. 9b. There is almost no change in Wrec with cycles. Hence, NBBLZTS-0.03 ceramic is fatigue-free from 1 to 105 cycles. Therefore, this material is useable for long term energy storage devices. 3.5 Conduction mechanism To understand the conduction, and relaxation mechanism in NBBLZTS-x ceramics, the impedance technique is carried out. Impedance Z is recognized to model AC impedance. Generally, a series of parallel resistance-capacitance (R-C circuits) are modeled for grain contribution, grain boundary, and electrode effect [48]. The impedance spectra for NBBLZTS-x ceramics are presented in Fig. 10a at 700 °C for all the samples. The Nyquist plots (-Z'' versus Z') are showed only one semicircle for all ceramics, and passing through the origin. Hence, the samples have only grain contribution. The resistance is estimated to decrease for NBBLZTS-x ≤ 0.06 samples, and start to increase for NBBLZTS-x ≥ 0.09 compositions. The increase of resistance might be related to impurity in the ceramics. Temperature-dependent impedance spectra for NBBLZTS-0, and NBBLZTS-0.03 ceramics are displayed, respectively in Fig. 10(b-c). The resistance is observed to decrease with increasing temperature as the nature of ceramics. Conductivity versus temperature plots are represented in Fig. 10d for all ceramics. Plots of ln(σ) with 1000/T are showed the linear for all the samples. This conductivity versus temperature plots are modeled by the Arrhenius equation as below [49]: =
exp (
!
" #
)
(4)
Where T, k, Ea, and σo are known as absolute temperature, Boltzmann constant, activation energy, and pre-exponential factor, respectively. Calculated Ea values are from ~ 1.71 eV to ~ 1.99 eV range as shown in Fig. 10d. The range of Ea corresponds to the oxygen vacancies, hence, defects are mainly related to the oxygen vacancies [50].
8
4. Conclusion Lead-free Na0.46Bi0.46Ba0.05La0.02Zr0.03Ti0.97-xSnxO3 (for x = 0, 0.03, 0.06, 0.09, 0.12, and 0.15) systems were prepared by conventional solid-state technique. Pseudocubic behavior of the samples was confirmed by the XRD. Also, the higher modified samples (NBBLZTS-x ≥ 0.06) were presented the secondary phase. Surface microstructure was ascribed the compact ceramics with increasing the average grain size. Electric-field induced polarization was revealed slim type hysteresis loops with compositions. The sample NBBLZTS-0.03 was presented the maximum difference between Pmax - Pr compared to others. For NBBLZTS-0.03 ceramic, the calculated Wrec ~ 1.58 J/cm3 with η ~ 71.7 % at E ~ 110 kV/cm are obtained. Also, temperature-dependent study of NBBLZTS-0.03 ceramic was revealed a high η ~ 88.6 % with Wrec ~ 1.53 J/cm3 at 110 °C for 100 kV/cm applied field. In addition, NBBLZTS-0.03 ceramic was presented the fatigue-free behavior from 1 to 105 cycles. Hence, NBBLZTS-0.03 ceramic might be applicable for large Wrec at ambient and wide temperature range.
Acknowledgements This work has been supported by the National Nature Science Foundation (51672220), the National Defense Science Foundation (32102060303), the Fundamental Research Funds for the Central Universities of NPU (3102019GHXM002), the SKLSP Project (2019-TZ-04), and the Open-end Fund of International Joint Research Laboratory of Henan Province for Underground Space Development and Disaster Prevention, Henan Polytechnic University, China. We would also like to thank the Analytical & Testing Center of Northwestern Polytechnical University for SEM, TEM, AFM, Raman and XRD test.
9
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Figure captions
Fig. 1. XRD patterns of NBBLZTS-x ceramics in the 2θ range of (a) 15 - 90°, (b) 39 - 40° and (c) 45 - 48°. Fig. 2. Raman spectrum for NBBLZTS-x ceramics at room temperature. NBBLZTS-0 sample is fitted using the Lorentzian function, presented using the dotted curves. Fig. 3. FESEM microstructure for NBBLZTS-x where (a) NBBLZTS-0, (b) NBBLZTS0.03, (c) NBBLZTS-0.06, (d) NBBLZTS-0.09, (e) NBBLZTS-0.12, and (f) NBBLZTS-0.15 ceramics. Fig. 4. ε' and tanδ versus temperature for NBBLZTS-x, where (a) NBBLZTS-0, (b) NBBLZTS-0.03, (c) NBBLZTS-0.06, (d) NBBLZTS-0.09, (e) NBBLZTS-0.12, and (f) NBBLZTS-0.15 compositions. Fig. 5. P-E and J-E curves for NBBLZTS-x, where (a) NBBLZTS-0, (b) NBBLZTS-0.03, (c) NBBLZTS-0.06, (d) NBBLZTS-0.09, (e) NBBLZTS-0.12, and (f) NBBLZTS-0.15 compositions. Fig. 6. (a) Calculated remnant polarization (Pr), maximum polarization (Pmax), and Pmax Pr with composition. (b) Storage density (Wrec), total supplied density (W), and η with compositions. Fig. 7. (a) Electric field (E) dependent polarization (P) for NBBLZTS-0.03 ceramic and (b) Calculated Wrec, W, and η at different applied field. Fig. 8. (a) P-E curves at different temperatures from 30 to 120 °C for NBBLZTS-0.03 ceramic, and (b) estimated Wrec, W, and η various temperature. Fig. 9. (a) Fatigue test of P-E curves from 1-105 cycles, and (b) calculated Pr, Pmax, and Wrec with cycles. Fig. 10. (a) AC impedance spectra for NBBLZTS-x at 700 °C, (b-c) impedance plots for NBBLZTS-0 and NBBLZTS-0.03 samples at different temperature, respectively, (d) estimated activation energy for NBBLZTS-x ceramics.
15
The author confirms, there is no conflict of interest exists in the submission of this manuscript, and the manuscript is approved by all authors for publication. I would like to declare on behalf of my co-authors that the work described was original research that has not been published previously, and not under consideration for publication elsewhere, in whole or in part. All the authors listed have approved the manuscript that is enclosed.