Translated Abstract
The problem of environmental pollution and energy consumption caused by social development forces us not only to seek cleaner energy but also to pursue safer and more efficient energy storage devices. Ferroelectric-based capacitors are widely used in the large capacity and small temperature difference system because of their high dielectric constant, fast charge and discharge process and excellent thermal stability. However, the low breakdown strength of ferroelectric-based ceramics restricts the further development of the application in energy storage field, so looking for new preparation technologies and modification methods has become the hot issue in this field.
Adding oxide through “bottom-up” method can effectively improve the breakdown strength of ferroelectric-based capacitors so as to increase the energy storage density. Particularly, core-shell nanoparticles used as blocks to construct composite ceramics can exhibit large energy storage density. In order to obtain capacitors with high performance as well as to investigate the influence of tunable shell thickness on microstructures and energy storage property of the finally sintered bulk ceramics. In this study, BaTiO3@SiO2 core-shell nanoparticles were successfully synthesized by a wet-chemical method, and they were used as precursors to fabricate bulk composite ceramics for investigating effects of the pristine nanostructured precursor on electrical properties of the ceramics. The pristine BaTiO3 nanoparticles coated with various homogenous SiO2 shells were obtained by controlling the concentration of tetraethyl orthosilicate (TEOS). The surface microstructure of the sintered bulk composite ceramics observed by scanning electron microscope (SEM) revealed that the SiO2 outer shell plays an important role in constructing the microstructure of the composite ceramics. In order to build relationships between microstructure and performance, leakage current density, dielectric test and ferroelectric test were performed. As a result, the optimum SiO2 loading range was confirmed and the maximum energy storage density obtained from BaTiO3@20wt%SiO2 was ~4.799J/cm3 at 370kV/cm and the efficiency reaches 99%.
This work not only demonstrates that nanoscale core-shell architecture is an effective strategy to improve the energy storage performance of the bulk ferroelectric-based ceramics but also revealed the relationships between microstructure and performance， which may provide valuable experience for the further development of ferroelectric-based capacitors.
Translated Keyword
[BaTiO3, Capacitor, Energy storage, Ferroelectric, Nano materials]
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