Dielectric responses of glass-added Ba0.95Ca0.05Zr0.3Ti0.7O3 ceramics for energy storage capacitors
Introduction
Utilization of lead-free BaTiO3-based dielectric ceramics in electric energy storage capacitors has attracted growing interest due to their high power density and reliability [1], [2], [3], [4]. On account of rising demands of high power systems, enhancing the energy storage capability of BaTiO3-based dielectric ceramics emerges as a great challenge [5]. It has been well recognized that a high electric breakdown strength and a large dielectric constant at working field favor a high energy storage density [6]. Unfortunately, BaTiO3-based dielectric ceramics suffer from an inevitable existence of flaws in their bulk (e.g. porosity), resulting in unsatisfactory breakdown strengths well below their intrinsic values.
In order to improve the densification of BaTiO3-based energy storage dielectrics, intensive studies have been performed on their preparation technology. It has been demonstrated that glass–ceramic route is a viable approach to this aim [5], [7], [8]. Moreover, liquid-phase sintering by adding glass additives serves as an alternative strategy for this purpose. BaTiO3-based ceramics with various glass additives added exhibited improved densification degrees [9], enhanced breakdown strengths [10] and modified energy storage properties [11], [12], [13].
On the other hand, it has been detected that adding glass additives into BaTiO3-based ceramics gave rise to an increase of dielectric loss [14], [15]. We found such a phenomenon in glass-added Ba0.95Sr0.05Zr0.2Ti0.8O3 dielectric ceramics for energy storage applications [13]. As compared with Ba0.95Sr0.05Zr0.2Ti0.8O3 ceramics, the dielectric loss of the glass-added ceramics was substantially increased, irrespective of an enhancement of their densification degree and electric insulation level with the glass addition. The increase of dielectric loss with added glass additives offers an intriguing topic of practical importance. Efforts on this issue would lead to a better understanding on contributing factors to the dielectric properties of BaTiO3-based ceramics.
In this work, we study the dielectric responses of Ba0.95Ca0.05Zr0.3Ti0.7O3 ceramics with addition of MgO–CaO–Al2O3–SiO2 glass additive. The purpose is to improve our understanding on the mechanisms underlying the dielectric behaviors.
Section snippets
Experimental
Ba0.95Ca0.05Zr0.3Ti0.7O3 powder was synthesized by a citrate method. The synthetic process was basically identical to our previous procedures for preparing BaZr0.2Ti0.8O3 and Ba0.6Sr0.4TiO3 powders [16], [17]. In the present work, the powder was calcined at 650 °C for 1 h in air. Glass powder with the nominal composition of 5% MgO–7% CaO–26% Al2O3–62% SiO2 (weight percent) was synthesized via a similar chemical route. The synthetic process has been reported in our earlier paper [13]. The glass
Characterization of structure and energy storage properties
Fig. 1 shows the XRD patterns of the ceramic specimens. A perovskite structure with cubic symmetry was identified for the specimen with x=0. For the glass-added specimens, small amounts of impurity phases, including Ba2TiSi2O8, BaAl2Si2O8 and Ca2Zr5Ti2O16, were detected in addition to a cubic perovskite phase. Similar impurity phases have been found in glass-added BaTiO3-based ceramics [9], [15] and BaTiO3-based glass–ceramics [5], [8]. As shown in Fig. 1, the impurity phases tend to develop
Conclusions
The structure and energy storage properties of Ba0.95Ca0.05Zr0.3Ti0.7O3 ceramics with varied contents of MgO–CaO–Al2O3–SiO2 glass additive added have been examined. The dielectric properties of the glass-added specimens have been investigated as a function of temperature and frequency. All the specimens displayed a relaxor-like behavior and the glass addition enhanced the degree of diffusion of the ferroelectric–paraelectric phase transition. The dielectric loss of the specimens was steadily
Acknowledgments
This work was supported by the National Natural Science Foundation of China (Nos. 51072146 and 50932004), the Ministry of Education (No. 20100143110006) and the Hubei Provincial Science and Technology Department (No. 2011CDA057).
References (34)
- et al.
Scr. Mater.
(2011) - et al.
J. Alloys Compd.
(2013) - et al.
Ceram. Int.
(2004) - et al.
J. Eur. Ceram. Soc.
(2010) - et al.
Mater. Res. Bull.
(2012) - et al.
Physica B
(2011) - et al.
J. Alloys Compd.
(2011) J. Phys. Chem. Solids
(1994)- et al.
J. Power Source
(2009) - et al.
Acta Mater.
(2006)
J. Eur. Ceram. Soc.
Solid State Ionics
J. Mater. Sci. —Mater. Electron.
J. Am. Ceram. Soc.
J. Am. Ceram. Soc.
J. Mater. Sci.
J. Electroceram.
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