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Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures
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Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures Zong-Yang Shen a, *, Yu Wang a, Yanxue Tang b, Yuanying Yu a, Wen-Qin Luo a, Xingcai Wang c, Yueming Li a, Zhumei Wang a, Fusheng Song a a Energy Storage and Conversion Ceramic Materials Engineering Laboratory of Jiangxi Province, China National Light Industry Key Laboratory of Functional Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen, 333403, China b Key Laboratory of Optoelectronic Material and Device, Shanghai Normal University, Shanghai, 200234, China c Chengdu Hongming UESTC Electronic New Materials Co., Ltd., Chengdu, 610100, China
a r t i c l e i n f o
a b s t r a c t
Article history: Received 7 February 2019 Received in revised form 23 May 2019 Accepted 15 June 2019 Available online xxx
A glass with composition of B2O3-Bi2O3-SiO2-CaO-BaO-Al2O3-ZrO2 (BBSZ) modified BaxSr1-xTiO3 (BST, x ¼ 0.3 and 0.4) ceramics were prepared by a conventional solid state reaction method abided by a formula of BST þ y%BBSZ (y ¼ 0, 2, 4, 7, and 10, in mass). The effect of BBSZ glass content on the structure, dielectric properties and energy storage characteristics of the ceramics was investigated. The dielectric constant reduced but the endurable electrical strength enhanced due to the BBSZ glass addition in BST ceramics. In particular, the dielectric loss of the ceramics at elevated temperature (e.g. 200 C) can be strongly suppressed from tand>20% to tand<3% after BBSZ glass modification. For Ba0.3Sr0.7TiO3þ2% BBSZ ceramics, an optimized energy storage density (g ¼ 0.63 J/cm3) and efficiency (h ¼ 91.6%) under an applied electric field of 160 kV/cm was obtained at room temperature. Meanwhile, the temperature dependent polarization-electric field (P-E) hysteresis loops were measured to evaluate the energy storage characteristics of the ceramics potential for high voltage capacitor application at elevated temperatures. © 2019 The Chinese Ceramic Society. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Keywords: Barium strontium titanate Glass modification Energy storage Ceramic capacitor
1. Introduction Next generation power electronics are eagerly searching for dielectric materials with high energy storage density, low loss, and good temperature stability for potential application in advanced pulsed power capacitors [1e3]. Basically, there are three kinds of ceramic materials for energy storage capacitors: linear dielectrics, ferroelectrics and antiferroelectrics [4]. Normal ferroelectric ceramics often show strong nonlinear characteristics with high saturated polarization (Ps). It is found that, however, their large remnant polarization (Pr) results in small recoverable energy storage density and low efficiency [5]. Relaxor ferroelectric ceramics exhibit slim hysteresis loop with relatively high Ps and low Pr, which are promising candidate materials for energy storage capacitors in case of further improving their temperature stability and breakdown strength [6e8]. Antiferroelectric ceramic materials have been reported to have super high recoverable energy storage density [9].
* Corresponding author. E-mail address: [email protected] (Z.-Y. Shen). Peer review under responsibility of The Chinese Ceramic Society.
Unfortunately, most antiferroelectrics for pulsed power energy storage capacitors are lead containing materials, such as (Pb,La)(Zr,Sn,Ti)O3, Pb(Tm,Nb)O3-Pb(Mg,Nb)O3, and PbHfO3, which will cause serious environmental issues due to the toxicity of lead [10e12]. Therefore, linear or weakly nonlinear lead-free ceramic materials with both high dielectric constant and breakdown strength are very attractive for energy storage capacitors in high power electronics. Of course, low loss under high electric field condition is necessary to guarantee low energy dissipation as Joule heat. Barium strontium titanate (BaxSr1-xTiO3, BST) is an environmentally friendly perovskite structural material, whose dielectric properties can be tailored by adjusting the mole ratio of Ba/Sr to meet a wide variety of applications in electronics, such as microwave phase shifters, dielectric capacitors, DRAM and PTC resistors [13e16]. In particular, BST (x 0.4) ceramics with Tc far below room temperature have been considered to be promising energy storage capacitor materials for pulsed power electronics [17]. Actually, Ba0.4Sr0.6TiO3 ceramics has been widely studied for energy storage capacitors owing to its high dielectric constant, low dielectric loss and moderate breakdown strength [18,19]. Our previous work also
https://doi.org/10.1016/j.jmat.2019.06.003 2352-8478/© 2019 The Chinese Ceramic Society. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003
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Table 1 The chemical composition of BBSZ glass. Chemical composition
B2O3
Bi2O3
SiO2
BaCO3
CaCO3
ZrO2
Al2O3
Mass fraction (%)
37.6
23.5
18.8
3.6
11.8
1.9
2.8
demonstrates that Ba0.3Sr0.7TiO3 ceramics is more suitable for pulsed power capacitors due to an optimized energy storage density and efficiency [20]. However, two important issues need to be addressed for BST ceramics: one is the relatively low breakdown strength (Eb~100 kV/cm), and the other is the rapidly increased dielectric loss at elevated temperatures (e.g. T > 120 C). It is well known that the energy density of capacitors is generally described R by the integral of g ¼ EdD, and for linear dielectrics, an ultimate energy density can be derived from the equation of g ¼ 0:5ε0 εr E2b , where g is the discharged energy density, ε0 (8.85 1012 F/m) the vacuum dielectric permittivity, εr the relative dielectric constant and Eb the breakdown strength [3,4,21]. Obviously, the ultimate energy density g is quadratic dependent on Eb, which makes enhancing the breakdown strength of BST ceramics as the primary choice for expanding their energy storage applications. On the other hand, the capacitors in power electronic circuits, e.g. bus capacitors, not only require a high but also a stable capacitance to supply a stabilized energy source at elevated temperatures (normally ~200 C and beyond), in addition to low losses requiring for the overall device to maintain its charge and to avoid self-heating [22]. Polymers are commonly used to form composites with ceramics to substantially enhance breakdown strength and thus serve as energy storage applications [21,23]. However, polymers are often suffering low working temperatures. Glasses exhibit a very high breakdown strength (Eb up to 103e104 kV/cm) similar to polymers, but have higher bonding strength with ceramics and better high temperature resistances than polymers [24,25]. Accordingly, it should be an interesting topic to enhance breakdown strength of the ceramics by using glass modification for energy storage capacitor applications even at elevated temperatures. As a matter of fact, different glasses modified BST ceramics have been reported to be capable of enhancing breakdown strength and then improving energy storage density [26e28]. Unfortunately, some details regarding to improve the dielectric properties for BST ceramics at elevated temperatures by glass modification are rarely investigated. Patel et al. reported enhanced energy storage performance of 3BaO3TiO2-B2O3 (BTBO) glass modified BT and BST-based ferroelectric ceramics, and evaluated their temperature dependent energy storage density up to 125 C. However, the obtained energy storage
density (<0.24 J/cm3) and efficiency (~52%) are actually relatively low [29,30]. Therefore, in the present work, a B2O3-Bi2O3-SiO2-CaOBaO-Al2O3-ZrO2 (BBSZ) glass is designed to modify BaxSr1-xTiO3 (BST, x ¼ 0.3 and 0.4) ceramics. The structure, frequency and temperature dependent dielectric properties, as well as temperature dependent P-E behaviors of the BBSZ modified BST ceramics are investigated as potential pulsed power capacitor materials for energy storage application at elevated temperatures. 2. Experimental B2O3-Bi2O3-SiO2-CaO-BaO-Al2O3-ZrO2 (BBSZ) glass was prepared using reagent grade B2O3 (98%), Bi2O3 (99.9%), SiO2 (99%), CaCO3 (99%), BaCO3 (99%), Al2O3 (99%) and ZrO2 (99.9%) from Sinopharm Chemical Reagent Co. Ltd., Shanghai, China as raw materials. These raw materials were weighed according to a chemical composition listed in Table 1, and then dry mixed, melted in an alumina crucible at 1100 C for 1 h. The molten glass was quenched in distilled water and then ball milled to sieve 100 mesh screen to form BBSZ powders. BaxSr1-xTiO3 (BST, x ¼ 0.3 and 0.4) ceramic powders were prepared by a solid state reaction route using raw materials of reagent-grade BaCO3 (99%), SrCO3 (99%), and TiO2 (98%) from Sinopharm Chemical Reagent Co. Ltd., Shanghai, China. The raw materials were weighed according to the stoichiometric composition of BST, and then mixed by planet ball milling for 12 h in a nylon bottle with deionized water and ZrO2 balls. After separating the balls, the mixed slurries were dried and calcined at 1200 C for 3 h in an alumina crucible to form BST powders. The BBSZ glass powders were mixed with BST powders abided by the formula of BST þ y%BBSZ, in which y ¼ 0, 2, 4, 7, and 10 (in mass), respectively. After ball milling for 12 h in deionized water, the mixed powders were dried and granulated using polyvinyl alcohol solution (PVA, 5%) as a binder. The granulated powders were then pressed into disks of 12 mm diameter and about 1.1 mm thick under 120 ± 10 MPa. The disks were first preheated in air at 650 C for 2 h to remove PVA binders, and then sintered at temperatures ranging from 1100 C to 1350 C for 3 h in air with a heating rate of 3 C/min and finally furnace-cooled to ambient temperature. An X-ray diffractometer (XRD, D8-Advanced, CuKa radiation) was utilized to determine the phase structure of sintered ceramics, and the data was analyzed by MDI Jade software. A field emission scanning electron microscope (FE-SEM, JSM-5610LV; JEOL, Japan) was applied to observe the microstructure features of the polished, thermally etched surface of the sintered ceramics. By polishing to about 0.6 mm thick, the ceramic samples were painted with silver
Fig. 1. XRD patterns of BaxSr1-xTiO3þy% BBSZ ceramics: (a) x ¼ 0.3 and (b) x ¼ 0.4.
Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003
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Fig. 2. SEM images of the polished and thermally etched surface of BaxSr1-xTiO3þy% BBSZ ceramics.
Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003
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Fig. 3. Frequency dependent (a,b) dielectric constant and (c,d) dielectric loss of BaxSr1-xTiO3þy% BBSZ ceramics at room temperature.
pastes on both sides, and then fired to electrodes at 800 C for 20 min. Room temperature relative dielectric constant εr and dielectric loss tand were measured by a precision impedance analyzer (HP4294A, Agilent) over a frequency range from 100 Hz to 1 MHz. The temperature dependence of the εr and tand at 1 kHz was determined using a precision impedance analyzer (HP4294A, Agilent) over a temperature range from 100 C to 450 C, being connected to a computer controlled temperature chamber. The room temperature polarization-electric field (P-E) hysteresis loops were examined using a Radiant precision workstation (TRek model 609B) based on a standard Sawyer-Tower circuit at 10 Hz. The temperature dependent P-E hysteresis loops from room temperature to 180 C were measured using an aixACCT TF2000 FE-HV ferroelectric test unit. The energy storage density and efficiency were evaluated by integrating the area between the polarization axis and the discharge curve in the P-E hysteresis loop of the ceramic samples. 3. Results and discussion Fig. 1 shows the XRD patterns of BST ceramics with different BBSZ glass doping content. It can be seen from Fig. 1 that all ceramic samples are indexed a main crystalline phase with cubic perovskite structure as strontium titanate (PDF#35e0734). However, an impurity phase can be detected for BBSZ modified BST samples as marked with asterisks in Fig. 1. This impurity phase is labeled as Ca3SiO5 (PDF#16e0406) through analysis, which should be due to a thermodynamic metastable crystallization of BBSZ glass [31]. The SEM images of the polished and thermally etched surface of BST ceramics with different BBSZ glass doping content are given in Fig. 2. Basically, the effect of BBSZ glass on the microstructure of BST ceramics with x ¼ 0.3 and x ¼ 0.4 is similar. For pure BST ceramics (y ¼ 0), the grain size is observed from several to tens of micrometers with clear grain boundaries, in accordance with the microstructural characteristics of BST ceramics reported in Refs. [26,32]. However, a small amount of BBSZ glass doping (y ¼ 2) completely changes the grain growth behavior of BST ceramics. The grain size decreases and some short rod-like grains are formed, and the grain boundaries become not clear. This phenomenon should be related to the following two aspects. On the one hand, the
appearance of glass liquid phase during sintering process will make the grains almost isolated by the glass phase at the grain boundary, which may hinder the transportation of ions to a certain extent and thereby inhibit the grain growth. On the other hand, the glass phase also may affect the diffusion and transportation behavior of ions during sintering process, resulting in an increasing growth rate of grains in a specific direction to form short rod-like shape. Such similar phenomenon can also be seen in other glass modified functional ceramics [29,33,34]. To further increase the doping content of BBSZ glass (y 4), microstructures of some large abnormally grown grains mixed with many fine grains can be observed, which should be due to the inevitably non-uniform distribution of glass, leading to an excessive liquid phase in some local areas, resulting in abnormal growth of grains on the contrary. Frequency dependent dielectric constant and loss of BST þ y% BBSZ ceramics measured at room temperature is shown in Fig. 3. Over the frequency ranging from 100 Hz to 1 MHz, as shown in Fig. 3a and b, the dielectric constant varies very stable, but gradually decreases with increasing BBSZ glass content, accompanied by a fairy low level dielectric loss of 103e104 as seen from Fig. 3c and d. Fig. 4 gives the temperature dependent dielectric constant and loss of BST þ y%BBSZ ceramics measured at 1 kHz. It can be detected from Fig. 4a and b that the Curie temperature (Tc) of pure Ba0.3Sr0.7TiO3 and Ba0.4Sr0.6TiO3 ceramics are 85 C and 60 C, respectively. These Tc show far below room temperature, which indicates that pure BST ceramics should be paraelectric cubic phase at room temperature in accordance with the main crystalline phase analyzed by XRD in Fig. 1. The dielectric constant peak at Tc can be strongly suppressed by BBSZ glass modification, which should be related to the internal clamping caused by the presence of immobile non-ferroelectric glass phase [29,30]. Of particular importance is that the modification of BBSZ glass not only effectively reduces the rapidly increasing dielectric constant of ceramics at high temperatures, but also significantly suppresses the loss dielectric relaxation peak at about 300 C as shown in Fig. 4c and d. Furthermore, as seen from the inset of Fig. 4c and d, when the measuring temperature is over 150 C, the dielectric loss sharply increases and reaches to 25.6% and 20.5% at 200 C, respectively, for pure Ba0.3Sr0.7TiO3 and Ba0.4Sr0.6TiO3 ceramics. However, the
Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003
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Fig. 4. Temperature dependent (a,b) dielectric constant and (c,d) dielectric loss of BaxSr1-xTiO3þy% BBSZ ceramics. Measurement was performed at 1 kHz upon heating process. The insets show an expanded view of dielectric loss from 150 C to 200 C.
dielectric loss of BBSZ glass modified BST ceramics still maintains a low level (<3%) even at 200 C. This phenomenon may be attributed to the fact that BBSZ glass phase on the grain boundaries can inhibit the charge transport at elevated temperatures, thus reducing the leakage loss. The polarization-electric field (P-E) hysteresis loops of BST þ y% BBSZ ceramics measured at room temperature are shown in Fig. 5. All P-E loops show slanted slim shape, implying weakly nonlinear characteristics of BBSZ modified BST ceramics. Due to the gradually increased dilution of non-ferroelectric BBSZ glass, i.e., the reduced volume fraction of the BST ferroelectric phase, the polarization of the ceramics slightly declines with increasing BBSZ content, in line with the observed decreasing dielectric constant shown in Fig. 3. However, the endurable electrical strength can be enhanced after BBSZ glass modification. For example, an endurable electric field raises from 110 kV/cm for pure Ba0.3Sr0.7TiO3 up to 160 kV/cm for Ba0.3Sr0.7TiO3þ2%BBSZ ceramics (Figs. 5a), and 90 kV/cm for pure Ba0.4Sr0.6TiO3 up to 130 kV/cm for Ba0.4Sr0.6TiO3þ2%BBSZ ceramics (Fig. 5b). The enhancement of endurable electrical strength should be mainly owing to the combined effect of the intrinsic high breakdown strength of glass [24,25] and the decrease of grain size caused by BBSZ glass modification as analyzed in Fig. 2, since electrical insulating ceramics with small grains have been reported
in favor of obtaining higher breakdown strength [35,36]. Room temperature energy storage density and efficiency of BST þ y%BBSZ ceramics at different applied electric fields can be calculated according to the P-E hysteresis loops and shown in Fig. 6. The calculation method can be found in previous reported references [3,4,20]. For Ba0.3Sr0.7TiO3þy%BBSZ ceramics, as shown in Fig. 6a and c, the energy storage density increases but efficiency decreases with increasing applied electric field, and an optimized energy storage density (g ¼ 0.63 J/cm3) and efficiency (h ¼ 91.6%) under an applied electric field of 160 kV/cm is obtained in Ba0.3Sr0.7TiO3þ2%BBSZ ceramics. Moreover, for Ba0.4Sr0.6TiO3þy% BBSZ ceramics, as shown in Fig. 6b and d, the energy storage density gradually increases with increasing applied electric field, while the efficiency first maintains a stable value and then drops sharply at an electric field inflexion point. Basically, such electric filed inflexion point increases with the increase of BBSZ glass content. For example, the electric filed inflexion point is 60 kV/cm for pure Ba0.4Sr0.6TiO3 ceramics, while increases to 110 kV/cm for Ba0.4Sr0.6TiO3þ10%BBSZ ceramics. This phenomenon should be owing to absorption of large amounts of energy induced by metastable paraelectric to ferroelectric phase transition under high electric field condition [37]. As discussed in our previous work, although the Tc of BST ceramics with x 0.4 is all far below room
Fig. 5. Room temperature polarization-electric field (P-E) hysteresis loops of BaxSr1-xTiO3þy% BBSZ ceramics: (a) x ¼ 0.3 and (b) x ¼ 0.4.
Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003
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Fig. 6. Room temperature (a,b) energy storage density and (c,d) efficiency of BaxSr1-xTiO3þy% BBSZ ceramics at different applied electric fields.
temperature, the metastable paraelectric phase must be more close to room temperature for BST ceramics with higher x values [20]. Accordingly, the field-induced metastable paraelectric to ferroelectric phase transition of Ba0.4Sr0.6TiO3 must be more likely to occur than that of Ba0.3Sr0.7TiO3. Of course, the addition of immobile non-ferroelectric BBSZ glass has a restrictive effect on the metastable paraelectric to ferroelectric phase transition, thus improving the electric filed inflexion point. Fig. 7 shows the P-E hysteresis loops of pure BST and BSTþ2% BBSZ ceramics measured from room temperature to 180 C applied with an electric field 70 kV/cm. As shown in Fig. 7, for pure BST ceramics (y ¼ 0), a round shape of P-E loop starts to appear at
120 C, indicating that leakage conductance increases obviously. However, for BSTþ2%BBSZ ceramics, a relatively good P-E loop can be obtained even at 180 C, which must be due to strongly suppressed leakage dielectric loss by BBSZ modification as analyzed in Fig. 4. According to the P-E loops data in Fig. 7, the temperature dependent energy storage density and efficiency are also calculated and shown in Fig. 8. Basically, the energy storage density and efficiency decrease with the increase of temperature. The use temperature of pure BST ceramics as energy storage capacitor applications is limited to lower than 120 C. However, for Ba0.3Sr0.7TiO3þ2%BBSZ ceramics, even if the temperature reaches to 180 C, whose energy storage density still remains 50% of the
Fig. 7. Polarization-electric field (P-E) hysteresis loops of BaxSr1-xTiO3þy% BBSZ ceramics measured from room temperature to 180 C applied with an electric field 70 kV/cm.
Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003
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Fig. 8. Temperature dependent energy storage density and efficiency of BaxSr1-xTiO3þy % BBSZ ceramics with an applied electric field 70 kV/cm.
density at room temperature, and the efficiency is still greater than 60%, demonstrating its potential application as energy storage capacitors at elevated temperatures. 4. Conclusions A BBSZ glass is designed to modify the dielectric properties, ferroelectric behaviors and energy storage characteristics of BST ceramics. The addition of BBSZ glass reduces the dielectric constant but enhances the endurable electrical strength of BST ceramics. BBSZ glass can not only apparently suppress the dielectric constant peak at Tc but also effectively reduce the rapidly increasing dielectric constant at high temperatures. Particularly, the dielectric loss of BST ceramics at 200 C can be remarkably reduced from tand>20% to tand<3% after BBSZ glass modification. For Ba0.3Sr0.7TiO3þ2%BBSZ ceramics, an optimized energy storage density (g ¼ 0.63 J/cm3) and efficiency (h ¼ 91.6%) under an applied electric field of 160 kV/cm can be obtained at room temperature, in addition to a relatively good energy storage characteristics up to 180 C, presenting a valuable capacitor material for application at elevated temperatures. Acknowledgments This work was supported by National Natural Science Foundation of China (51767010) and Science & Technology Key Research Project of Jiangxi Provincial Education Department (GJJ170760). References [1] Chu BJ, Zhou X, Ren KL, Neese B, Lin M, Wang Q, et al. A dielectric polymer with high electric energy density and fast discharge speed. Science 2006;313: 334e6. [2] Zhao L, Liu Q, Gao J, Zhang S, Li JF. Lead-free antiferroelectric silver niobate tantalate with high energy storage performance. Adv Mater 2017;29: 1701824. [3] Yao Z, Song Z, Hao H, Yu Z, Cao M, Zhang S, et al. Homogeneous/inhomogeneous-structured dielectrics and their energy-storage performances. Adv Mater 2017;29:1601727. [4] Burn I, Smyth DM. Energy storage in ceramic dielectrics. J Mater Sci 1972;7: 339e43. [5] Love GR. Energy storage in ceramic dielectrics. J Am Ceram Soc 1990;73: 323e8. [6] Wang T, Jin L, Li C, Hu Q, Wei X. Relaxor ferroelectric BaTiO3-Bi(Mg2/3Nb1/3)O3 ceramics for energy storage application. J Am Ceram Soc 2015;98:559e66. [7] Wu L, Wang X, Li L. Lead-free BaTiO3-Bi(Zn2/3Nb1/3)O3 weakly coupled relaxor
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Effect of BBS-based frit on the low temperature sintering and electrical properties of KNN lead-free piezoceramics. Int J Appl Ceram Technol 2013;10:866e72. [35] Ye Y, Zhang SC, Dogan F, Schamiloglu E, Gaudet J, Castro P, et al. Influence of nanocrystalline grain size on the breakdown strength of ceramic dielectrics. PPC. IEEE International Pulsed Power Conference 2003;1:719e22. 2003. [36] Shen ZY, Li Y, Luo WQ, Wang Z, Gu X, Liao R. Structure and dielectric properties of NdxSr1-xTiO3 ceramics for energy storage application. J Mater Sci Mater Electron 2013;24:704e10. [37] Zheludev IS. Physics of crystalline dielectrics. New York: Springer US; 2012.
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Z.-Y. Shen et al. / Journal of Materiomics xxx (xxxx) xxx Zong-Yang Shen is currently a professor and vice dean of School of Materials Science and Engineering, Jingdezhen Ceramic Institute. He obtained his PhD degree at School of Materials Science and Engineering, Wuhan University of Technology, in 2007. Afterward, he joined Prof. Jing-Feng Li's group in Tsinghua University, as a Postdoctoral Research Fellow. In the year 2010, he joined Jingdezhen Ceramic Institute, and studied in MRI, Pennsylvania State University, as a visiting scholar in Prof. Shujun Zhang's group from 2012 to 2013. His research interests include lead-free piezoelectric ceramics, high Curie temperature piezoelectric ceramics and devices, energy storage ceramics for high voltage capacitors and traditional ceramics. He was granted the Ninth Science and Technology Nomination Award for young scientists from the Chinese Ceramic Society in 2011 and the Polish Ceramic Society Award in 2018. He authored/co-authored over 120 publications and 15 patents, as well as one ISO international standard.
Aerospace Science and Technology. He was granted second-class award of Chengdu Scientific and Technological Process in 2008.
Yanxue Tang is currently an associate professor of Shanghai Normal University. She obtained her PhD degree in 2007 from Shanghai Institute of Ceramics, Chinese Academy of Sciences and awarded excellent graduates of Shanghai. She studied in MRI, Pennsylvania State University, as a visiting scholar in Prof. Tomas R. Shrout's group for one year. Her research interests include ferroelectric, piezoelectric and pyroelectric single crystals and ceramics, as well as their applications in transducers, infrared detectors and imaging devices. She authored/co-authored over 50 publications and one patent.
Yueming Li is a currently a distinguished professor and dean of School of Materials Science and Engineering, Jingdezhen Ceramic Institute, and also director of China National Light Industry Key Laboratory of Functional Ceramic Materials and Jiangxi Energy Storage and Conversion Ceramic Materials Engineering Laboratory. He received his PhD degree at School of Materials Science and Engineering, Wuhan University of Technology, in 2004. His research interests include lead-free piezoelectric ceramics and devices, microwave dielectric ceramics, environmentally friendly red pigments for ceramic decorative applications and low expansion ceramic materials. He is a council member of Advanced Ceramics Branch of the Chinese Ceramic Society, vice chairman of Jingdezhen Science and Technology Association and on the editorial board of Journal of Electronic Components and Materials and Journal of Ceramics. He was granted the second-class award of National Scientific and Technological Process in 2008, the first-class award of Jiangxi Scientific and Technological Process in 2007, Hubei Excellent Doctoral Dissertation Award in 2006, and the Polish Ceramic Society Award in 2018. He authored/co-authored over 200 publications and 19 patents as well as one ISO international standard.
Xingcai Wang is currently a Deputy Engineer of Chengdu Hongming UESTC Electronic New Materials Co., Ltd. and Chief Engineer of Chip Capacitor Plant. He mainly engaged in research and development of multi-layer ceramic capacitors (MLCC), including application verification, reliability and failure analysis technology. He is a member of the Standard Group of Aerospace Grade Multilayer Ceramic Capacitors and Working Group of the Eighth Academy of
Zhumei Wang is currently an associate professor of Jingdezhen Ceramic Institute. She obtained her bachelor's degree in 1994 from Harbin Institute of Technology. Her research interests include nanostructured functional ceramics and environmentally friendly red pigments for ceramic decorative applications.
Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003
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Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures Zong-Yang Shen a, *, Yu Wang a, Yanxue Tang b, Yuanying Yu a, Wen-Qin Luo a, Xingcai Wang c, Yueming Li a, Zhumei Wang a, Fusheng Song a a Energy Storage and Conversion Ceramic Materials Engineering Laboratory of Jiangxi Province, China National Light Industry Key Laboratory of Functional Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jingdezhen, 333403, China b Key Laboratory of Optoelectronic Material and Device, Shanghai Normal University, Shanghai, 200234, China c Chengdu Hongming UESTC Electronic New Materials Co., Ltd., Chengdu, 610100, China
a r t i c l e i n f o
a b s t r a c t
Article history: Received 7 February 2019 Received in revised form 23 May 2019 Accepted 15 June 2019 Available online xxx
A glass with composition of B2O3-Bi2O3-SiO2-CaO-BaO-Al2O3-ZrO2 (BBSZ) modified BaxSr1-xTiO3 (BST, x ¼ 0.3 and 0.4) ceramics were prepared by a conventional solid state reaction method abided by a formula of BST þ y%BBSZ (y ¼ 0, 2, 4, 7, and 10, in mass). The effect of BBSZ glass content on the structure, dielectric properties and energy storage characteristics of the ceramics was investigated. The dielectric constant reduced but the endurable electrical strength enhanced due to the BBSZ glass addition in BST ceramics. In particular, the dielectric loss of the ceramics at elevated temperature (e.g. 200 C) can be strongly suppressed from tand>20% to tand<3% after BBSZ glass modification. For Ba0.3Sr0.7TiO3þ2% BBSZ ceramics, an optimized energy storage density (g ¼ 0.63 J/cm3) and efficiency (h ¼ 91.6%) under an applied electric field of 160 kV/cm was obtained at room temperature. Meanwhile, the temperature dependent polarization-electric field (P-E) hysteresis loops were measured to evaluate the energy storage characteristics of the ceramics potential for high voltage capacitor application at elevated temperatures. © 2019 The Chinese Ceramic Society. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Keywords: Barium strontium titanate Glass modification Energy storage Ceramic capacitor
1. Introduction Next generation power electronics are eagerly searching for dielectric materials with high energy storage density, low loss, and good temperature stability for potential application in advanced pulsed power capacitors [1e3]. Basically, there are three kinds of ceramic materials for energy storage capacitors: linear dielectrics, ferroelectrics and antiferroelectrics [4]. Normal ferroelectric ceramics often show strong nonlinear characteristics with high saturated polarization (Ps). It is found that, however, their large remnant polarization (Pr) results in small recoverable energy storage density and low efficiency [5]. Relaxor ferroelectric ceramics exhibit slim hysteresis loop with relatively high Ps and low Pr, which are promising candidate materials for energy storage capacitors in case of further improving their temperature stability and breakdown strength [6e8]. Antiferroelectric ceramic materials have been reported to have super high recoverable energy storage density [9].
* Corresponding author. E-mail address: [email protected] (Z.-Y. Shen). Peer review under responsibility of The Chinese Ceramic Society.
Unfortunately, most antiferroelectrics for pulsed power energy storage capacitors are lead containing materials, such as (Pb,La)(Zr,Sn,Ti)O3, Pb(Tm,Nb)O3-Pb(Mg,Nb)O3, and PbHfO3, which will cause serious environmental issues due to the toxicity of lead [10e12]. Therefore, linear or weakly nonlinear lead-free ceramic materials with both high dielectric constant and breakdown strength are very attractive for energy storage capacitors in high power electronics. Of course, low loss under high electric field condition is necessary to guarantee low energy dissipation as Joule heat. Barium strontium titanate (BaxSr1-xTiO3, BST) is an environmentally friendly perovskite structural material, whose dielectric properties can be tailored by adjusting the mole ratio of Ba/Sr to meet a wide variety of applications in electronics, such as microwave phase shifters, dielectric capacitors, DRAM and PTC resistors [13e16]. In particular, BST (x 0.4) ceramics with Tc far below room temperature have been considered to be promising energy storage capacitor materials for pulsed power electronics [17]. Actually, Ba0.4Sr0.6TiO3 ceramics has been widely studied for energy storage capacitors owing to its high dielectric constant, low dielectric loss and moderate breakdown strength [18,19]. Our previous work also
https://doi.org/10.1016/j.jmat.2019.06.003 2352-8478/© 2019 The Chinese Ceramic Society. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003
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Table 1 The chemical composition of BBSZ glass. Chemical composition
B2O3
Bi2O3
SiO2
BaCO3
CaCO3
ZrO2
Al2O3
Mass fraction (%)
37.6
23.5
18.8
3.6
11.8
1.9
2.8
demonstrates that Ba0.3Sr0.7TiO3 ceramics is more suitable for pulsed power capacitors due to an optimized energy storage density and efficiency [20]. However, two important issues need to be addressed for BST ceramics: one is the relatively low breakdown strength (Eb~100 kV/cm), and the other is the rapidly increased dielectric loss at elevated temperatures (e.g. T > 120 C). It is well known that the energy density of capacitors is generally described R by the integral of g ¼ EdD, and for linear dielectrics, an ultimate energy density can be derived from the equation of g ¼ 0:5ε0 εr E2b , where g is the discharged energy density, ε0 (8.85 1012 F/m) the vacuum dielectric permittivity, εr the relative dielectric constant and Eb the breakdown strength [3,4,21]. Obviously, the ultimate energy density g is quadratic dependent on Eb, which makes enhancing the breakdown strength of BST ceramics as the primary choice for expanding their energy storage applications. On the other hand, the capacitors in power electronic circuits, e.g. bus capacitors, not only require a high but also a stable capacitance to supply a stabilized energy source at elevated temperatures (normally ~200 C and beyond), in addition to low losses requiring for the overall device to maintain its charge and to avoid self-heating [22]. Polymers are commonly used to form composites with ceramics to substantially enhance breakdown strength and thus serve as energy storage applications [21,23]. However, polymers are often suffering low working temperatures. Glasses exhibit a very high breakdown strength (Eb up to 103e104 kV/cm) similar to polymers, but have higher bonding strength with ceramics and better high temperature resistances than polymers [24,25]. Accordingly, it should be an interesting topic to enhance breakdown strength of the ceramics by using glass modification for energy storage capacitor applications even at elevated temperatures. As a matter of fact, different glasses modified BST ceramics have been reported to be capable of enhancing breakdown strength and then improving energy storage density [26e28]. Unfortunately, some details regarding to improve the dielectric properties for BST ceramics at elevated temperatures by glass modification are rarely investigated. Patel et al. reported enhanced energy storage performance of 3BaO3TiO2-B2O3 (BTBO) glass modified BT and BST-based ferroelectric ceramics, and evaluated their temperature dependent energy storage density up to 125 C. However, the obtained energy storage
density (<0.24 J/cm3) and efficiency (~52%) are actually relatively low [29,30]. Therefore, in the present work, a B2O3-Bi2O3-SiO2-CaOBaO-Al2O3-ZrO2 (BBSZ) glass is designed to modify BaxSr1-xTiO3 (BST, x ¼ 0.3 and 0.4) ceramics. The structure, frequency and temperature dependent dielectric properties, as well as temperature dependent P-E behaviors of the BBSZ modified BST ceramics are investigated as potential pulsed power capacitor materials for energy storage application at elevated temperatures. 2. Experimental B2O3-Bi2O3-SiO2-CaO-BaO-Al2O3-ZrO2 (BBSZ) glass was prepared using reagent grade B2O3 (98%), Bi2O3 (99.9%), SiO2 (99%), CaCO3 (99%), BaCO3 (99%), Al2O3 (99%) and ZrO2 (99.9%) from Sinopharm Chemical Reagent Co. Ltd., Shanghai, China as raw materials. These raw materials were weighed according to a chemical composition listed in Table 1, and then dry mixed, melted in an alumina crucible at 1100 C for 1 h. The molten glass was quenched in distilled water and then ball milled to sieve 100 mesh screen to form BBSZ powders. BaxSr1-xTiO3 (BST, x ¼ 0.3 and 0.4) ceramic powders were prepared by a solid state reaction route using raw materials of reagent-grade BaCO3 (99%), SrCO3 (99%), and TiO2 (98%) from Sinopharm Chemical Reagent Co. Ltd., Shanghai, China. The raw materials were weighed according to the stoichiometric composition of BST, and then mixed by planet ball milling for 12 h in a nylon bottle with deionized water and ZrO2 balls. After separating the balls, the mixed slurries were dried and calcined at 1200 C for 3 h in an alumina crucible to form BST powders. The BBSZ glass powders were mixed with BST powders abided by the formula of BST þ y%BBSZ, in which y ¼ 0, 2, 4, 7, and 10 (in mass), respectively. After ball milling for 12 h in deionized water, the mixed powders were dried and granulated using polyvinyl alcohol solution (PVA, 5%) as a binder. The granulated powders were then pressed into disks of 12 mm diameter and about 1.1 mm thick under 120 ± 10 MPa. The disks were first preheated in air at 650 C for 2 h to remove PVA binders, and then sintered at temperatures ranging from 1100 C to 1350 C for 3 h in air with a heating rate of 3 C/min and finally furnace-cooled to ambient temperature. An X-ray diffractometer (XRD, D8-Advanced, CuKa radiation) was utilized to determine the phase structure of sintered ceramics, and the data was analyzed by MDI Jade software. A field emission scanning electron microscope (FE-SEM, JSM-5610LV; JEOL, Japan) was applied to observe the microstructure features of the polished, thermally etched surface of the sintered ceramics. By polishing to about 0.6 mm thick, the ceramic samples were painted with silver
Fig. 1. XRD patterns of BaxSr1-xTiO3þy% BBSZ ceramics: (a) x ¼ 0.3 and (b) x ¼ 0.4.
Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003
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Fig. 2. SEM images of the polished and thermally etched surface of BaxSr1-xTiO3þy% BBSZ ceramics.
Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003
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Fig. 3. Frequency dependent (a,b) dielectric constant and (c,d) dielectric loss of BaxSr1-xTiO3þy% BBSZ ceramics at room temperature.
pastes on both sides, and then fired to electrodes at 800 C for 20 min. Room temperature relative dielectric constant εr and dielectric loss tand were measured by a precision impedance analyzer (HP4294A, Agilent) over a frequency range from 100 Hz to 1 MHz. The temperature dependence of the εr and tand at 1 kHz was determined using a precision impedance analyzer (HP4294A, Agilent) over a temperature range from 100 C to 450 C, being connected to a computer controlled temperature chamber. The room temperature polarization-electric field (P-E) hysteresis loops were examined using a Radiant precision workstation (TRek model 609B) based on a standard Sawyer-Tower circuit at 10 Hz. The temperature dependent P-E hysteresis loops from room temperature to 180 C were measured using an aixACCT TF2000 FE-HV ferroelectric test unit. The energy storage density and efficiency were evaluated by integrating the area between the polarization axis and the discharge curve in the P-E hysteresis loop of the ceramic samples. 3. Results and discussion Fig. 1 shows the XRD patterns of BST ceramics with different BBSZ glass doping content. It can be seen from Fig. 1 that all ceramic samples are indexed a main crystalline phase with cubic perovskite structure as strontium titanate (PDF#35e0734). However, an impurity phase can be detected for BBSZ modified BST samples as marked with asterisks in Fig. 1. This impurity phase is labeled as Ca3SiO5 (PDF#16e0406) through analysis, which should be due to a thermodynamic metastable crystallization of BBSZ glass [31]. The SEM images of the polished and thermally etched surface of BST ceramics with different BBSZ glass doping content are given in Fig. 2. Basically, the effect of BBSZ glass on the microstructure of BST ceramics with x ¼ 0.3 and x ¼ 0.4 is similar. For pure BST ceramics (y ¼ 0), the grain size is observed from several to tens of micrometers with clear grain boundaries, in accordance with the microstructural characteristics of BST ceramics reported in Refs. [26,32]. However, a small amount of BBSZ glass doping (y ¼ 2) completely changes the grain growth behavior of BST ceramics. The grain size decreases and some short rod-like grains are formed, and the grain boundaries become not clear. This phenomenon should be related to the following two aspects. On the one hand, the
appearance of glass liquid phase during sintering process will make the grains almost isolated by the glass phase at the grain boundary, which may hinder the transportation of ions to a certain extent and thereby inhibit the grain growth. On the other hand, the glass phase also may affect the diffusion and transportation behavior of ions during sintering process, resulting in an increasing growth rate of grains in a specific direction to form short rod-like shape. Such similar phenomenon can also be seen in other glass modified functional ceramics [29,33,34]. To further increase the doping content of BBSZ glass (y 4), microstructures of some large abnormally grown grains mixed with many fine grains can be observed, which should be due to the inevitably non-uniform distribution of glass, leading to an excessive liquid phase in some local areas, resulting in abnormal growth of grains on the contrary. Frequency dependent dielectric constant and loss of BST þ y% BBSZ ceramics measured at room temperature is shown in Fig. 3. Over the frequency ranging from 100 Hz to 1 MHz, as shown in Fig. 3a and b, the dielectric constant varies very stable, but gradually decreases with increasing BBSZ glass content, accompanied by a fairy low level dielectric loss of 103e104 as seen from Fig. 3c and d. Fig. 4 gives the temperature dependent dielectric constant and loss of BST þ y%BBSZ ceramics measured at 1 kHz. It can be detected from Fig. 4a and b that the Curie temperature (Tc) of pure Ba0.3Sr0.7TiO3 and Ba0.4Sr0.6TiO3 ceramics are 85 C and 60 C, respectively. These Tc show far below room temperature, which indicates that pure BST ceramics should be paraelectric cubic phase at room temperature in accordance with the main crystalline phase analyzed by XRD in Fig. 1. The dielectric constant peak at Tc can be strongly suppressed by BBSZ glass modification, which should be related to the internal clamping caused by the presence of immobile non-ferroelectric glass phase [29,30]. Of particular importance is that the modification of BBSZ glass not only effectively reduces the rapidly increasing dielectric constant of ceramics at high temperatures, but also significantly suppresses the loss dielectric relaxation peak at about 300 C as shown in Fig. 4c and d. Furthermore, as seen from the inset of Fig. 4c and d, when the measuring temperature is over 150 C, the dielectric loss sharply increases and reaches to 25.6% and 20.5% at 200 C, respectively, for pure Ba0.3Sr0.7TiO3 and Ba0.4Sr0.6TiO3 ceramics. However, the
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Fig. 4. Temperature dependent (a,b) dielectric constant and (c,d) dielectric loss of BaxSr1-xTiO3þy% BBSZ ceramics. Measurement was performed at 1 kHz upon heating process. The insets show an expanded view of dielectric loss from 150 C to 200 C.
dielectric loss of BBSZ glass modified BST ceramics still maintains a low level (<3%) even at 200 C. This phenomenon may be attributed to the fact that BBSZ glass phase on the grain boundaries can inhibit the charge transport at elevated temperatures, thus reducing the leakage loss. The polarization-electric field (P-E) hysteresis loops of BST þ y% BBSZ ceramics measured at room temperature are shown in Fig. 5. All P-E loops show slanted slim shape, implying weakly nonlinear characteristics of BBSZ modified BST ceramics. Due to the gradually increased dilution of non-ferroelectric BBSZ glass, i.e., the reduced volume fraction of the BST ferroelectric phase, the polarization of the ceramics slightly declines with increasing BBSZ content, in line with the observed decreasing dielectric constant shown in Fig. 3. However, the endurable electrical strength can be enhanced after BBSZ glass modification. For example, an endurable electric field raises from 110 kV/cm for pure Ba0.3Sr0.7TiO3 up to 160 kV/cm for Ba0.3Sr0.7TiO3þ2%BBSZ ceramics (Figs. 5a), and 90 kV/cm for pure Ba0.4Sr0.6TiO3 up to 130 kV/cm for Ba0.4Sr0.6TiO3þ2%BBSZ ceramics (Fig. 5b). The enhancement of endurable electrical strength should be mainly owing to the combined effect of the intrinsic high breakdown strength of glass [24,25] and the decrease of grain size caused by BBSZ glass modification as analyzed in Fig. 2, since electrical insulating ceramics with small grains have been reported
in favor of obtaining higher breakdown strength [35,36]. Room temperature energy storage density and efficiency of BST þ y%BBSZ ceramics at different applied electric fields can be calculated according to the P-E hysteresis loops and shown in Fig. 6. The calculation method can be found in previous reported references [3,4,20]. For Ba0.3Sr0.7TiO3þy%BBSZ ceramics, as shown in Fig. 6a and c, the energy storage density increases but efficiency decreases with increasing applied electric field, and an optimized energy storage density (g ¼ 0.63 J/cm3) and efficiency (h ¼ 91.6%) under an applied electric field of 160 kV/cm is obtained in Ba0.3Sr0.7TiO3þ2%BBSZ ceramics. Moreover, for Ba0.4Sr0.6TiO3þy% BBSZ ceramics, as shown in Fig. 6b and d, the energy storage density gradually increases with increasing applied electric field, while the efficiency first maintains a stable value and then drops sharply at an electric field inflexion point. Basically, such electric filed inflexion point increases with the increase of BBSZ glass content. For example, the electric filed inflexion point is 60 kV/cm for pure Ba0.4Sr0.6TiO3 ceramics, while increases to 110 kV/cm for Ba0.4Sr0.6TiO3þ10%BBSZ ceramics. This phenomenon should be owing to absorption of large amounts of energy induced by metastable paraelectric to ferroelectric phase transition under high electric field condition [37]. As discussed in our previous work, although the Tc of BST ceramics with x 0.4 is all far below room
Fig. 5. Room temperature polarization-electric field (P-E) hysteresis loops of BaxSr1-xTiO3þy% BBSZ ceramics: (a) x ¼ 0.3 and (b) x ¼ 0.4.
Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003
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Fig. 6. Room temperature (a,b) energy storage density and (c,d) efficiency of BaxSr1-xTiO3þy% BBSZ ceramics at different applied electric fields.
temperature, the metastable paraelectric phase must be more close to room temperature for BST ceramics with higher x values [20]. Accordingly, the field-induced metastable paraelectric to ferroelectric phase transition of Ba0.4Sr0.6TiO3 must be more likely to occur than that of Ba0.3Sr0.7TiO3. Of course, the addition of immobile non-ferroelectric BBSZ glass has a restrictive effect on the metastable paraelectric to ferroelectric phase transition, thus improving the electric filed inflexion point. Fig. 7 shows the P-E hysteresis loops of pure BST and BSTþ2% BBSZ ceramics measured from room temperature to 180 C applied with an electric field 70 kV/cm. As shown in Fig. 7, for pure BST ceramics (y ¼ 0), a round shape of P-E loop starts to appear at
120 C, indicating that leakage conductance increases obviously. However, for BSTþ2%BBSZ ceramics, a relatively good P-E loop can be obtained even at 180 C, which must be due to strongly suppressed leakage dielectric loss by BBSZ modification as analyzed in Fig. 4. According to the P-E loops data in Fig. 7, the temperature dependent energy storage density and efficiency are also calculated and shown in Fig. 8. Basically, the energy storage density and efficiency decrease with the increase of temperature. The use temperature of pure BST ceramics as energy storage capacitor applications is limited to lower than 120 C. However, for Ba0.3Sr0.7TiO3þ2%BBSZ ceramics, even if the temperature reaches to 180 C, whose energy storage density still remains 50% of the
Fig. 7. Polarization-electric field (P-E) hysteresis loops of BaxSr1-xTiO3þy% BBSZ ceramics measured from room temperature to 180 C applied with an electric field 70 kV/cm.
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Fig. 8. Temperature dependent energy storage density and efficiency of BaxSr1-xTiO3þy % BBSZ ceramics with an applied electric field 70 kV/cm.
density at room temperature, and the efficiency is still greater than 60%, demonstrating its potential application as energy storage capacitors at elevated temperatures. 4. Conclusions A BBSZ glass is designed to modify the dielectric properties, ferroelectric behaviors and energy storage characteristics of BST ceramics. The addition of BBSZ glass reduces the dielectric constant but enhances the endurable electrical strength of BST ceramics. BBSZ glass can not only apparently suppress the dielectric constant peak at Tc but also effectively reduce the rapidly increasing dielectric constant at high temperatures. Particularly, the dielectric loss of BST ceramics at 200 C can be remarkably reduced from tand>20% to tand<3% after BBSZ glass modification. For Ba0.3Sr0.7TiO3þ2%BBSZ ceramics, an optimized energy storage density (g ¼ 0.63 J/cm3) and efficiency (h ¼ 91.6%) under an applied electric field of 160 kV/cm can be obtained at room temperature, in addition to a relatively good energy storage characteristics up to 180 C, presenting a valuable capacitor material for application at elevated temperatures. Acknowledgments This work was supported by National Natural Science Foundation of China (51767010) and Science & Technology Key Research Project of Jiangxi Provincial Education Department (GJJ170760). References [1] Chu BJ, Zhou X, Ren KL, Neese B, Lin M, Wang Q, et al. A dielectric polymer with high electric energy density and fast discharge speed. Science 2006;313: 334e6. [2] Zhao L, Liu Q, Gao J, Zhang S, Li JF. Lead-free antiferroelectric silver niobate tantalate with high energy storage performance. Adv Mater 2017;29: 1701824. [3] Yao Z, Song Z, Hao H, Yu Z, Cao M, Zhang S, et al. Homogeneous/inhomogeneous-structured dielectrics and their energy-storage performances. Adv Mater 2017;29:1601727. [4] Burn I, Smyth DM. Energy storage in ceramic dielectrics. J Mater Sci 1972;7: 339e43. [5] Love GR. Energy storage in ceramic dielectrics. J Am Ceram Soc 1990;73: 323e8. [6] Wang T, Jin L, Li C, Hu Q, Wei X. Relaxor ferroelectric BaTiO3-Bi(Mg2/3Nb1/3)O3 ceramics for energy storage application. J Am Ceram Soc 2015;98:559e66. [7] Wu L, Wang X, Li L. Lead-free BaTiO3-Bi(Zn2/3Nb1/3)O3 weakly coupled relaxor
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Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003
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Z.-Y. Shen et al. / Journal of Materiomics xxx (xxxx) xxx Zong-Yang Shen is currently a professor and vice dean of School of Materials Science and Engineering, Jingdezhen Ceramic Institute. He obtained his PhD degree at School of Materials Science and Engineering, Wuhan University of Technology, in 2007. Afterward, he joined Prof. Jing-Feng Li's group in Tsinghua University, as a Postdoctoral Research Fellow. In the year 2010, he joined Jingdezhen Ceramic Institute, and studied in MRI, Pennsylvania State University, as a visiting scholar in Prof. Shujun Zhang's group from 2012 to 2013. His research interests include lead-free piezoelectric ceramics, high Curie temperature piezoelectric ceramics and devices, energy storage ceramics for high voltage capacitors and traditional ceramics. He was granted the Ninth Science and Technology Nomination Award for young scientists from the Chinese Ceramic Society in 2011 and the Polish Ceramic Society Award in 2018. He authored/co-authored over 120 publications and 15 patents, as well as one ISO international standard.
Aerospace Science and Technology. He was granted second-class award of Chengdu Scientific and Technological Process in 2008.
Yanxue Tang is currently an associate professor of Shanghai Normal University. She obtained her PhD degree in 2007 from Shanghai Institute of Ceramics, Chinese Academy of Sciences and awarded excellent graduates of Shanghai. She studied in MRI, Pennsylvania State University, as a visiting scholar in Prof. Tomas R. Shrout's group for one year. Her research interests include ferroelectric, piezoelectric and pyroelectric single crystals and ceramics, as well as their applications in transducers, infrared detectors and imaging devices. She authored/co-authored over 50 publications and one patent.
Yueming Li is a currently a distinguished professor and dean of School of Materials Science and Engineering, Jingdezhen Ceramic Institute, and also director of China National Light Industry Key Laboratory of Functional Ceramic Materials and Jiangxi Energy Storage and Conversion Ceramic Materials Engineering Laboratory. He received his PhD degree at School of Materials Science and Engineering, Wuhan University of Technology, in 2004. His research interests include lead-free piezoelectric ceramics and devices, microwave dielectric ceramics, environmentally friendly red pigments for ceramic decorative applications and low expansion ceramic materials. He is a council member of Advanced Ceramics Branch of the Chinese Ceramic Society, vice chairman of Jingdezhen Science and Technology Association and on the editorial board of Journal of Electronic Components and Materials and Journal of Ceramics. He was granted the second-class award of National Scientific and Technological Process in 2008, the first-class award of Jiangxi Scientific and Technological Process in 2007, Hubei Excellent Doctoral Dissertation Award in 2006, and the Polish Ceramic Society Award in 2018. He authored/co-authored over 200 publications and 19 patents as well as one ISO international standard.
Xingcai Wang is currently a Deputy Engineer of Chengdu Hongming UESTC Electronic New Materials Co., Ltd. and Chief Engineer of Chip Capacitor Plant. He mainly engaged in research and development of multi-layer ceramic capacitors (MLCC), including application verification, reliability and failure analysis technology. He is a member of the Standard Group of Aerospace Grade Multilayer Ceramic Capacitors and Working Group of the Eighth Academy of
Zhumei Wang is currently an associate professor of Jingdezhen Ceramic Institute. She obtained her bachelor's degree in 1994 from Harbin Institute of Technology. Her research interests include nanostructured functional ceramics and environmentally friendly red pigments for ceramic decorative applications.
Please cite this article as: Shen Z-Y et al., Glass modified barium strontium titanate ceramics for energy storage capacitor at elevated temperatures, Journal of Materiomics, https://doi.org/10.1016/j.jmat.2019.06.003