High energy storage density and high reliability dielectric energy storage materials play an increasingly important role in various power and electronic systems, especially in the field of high energy pulse power technology. Related devices and products are becoming smaller The development of light, multi-functional and multi-functional directions puts higher requirements on the storage density of devices. The key to improving the energy storage characteristics of devices is to develop dielectric materials with high energy storage density. Application of antiferroelectric (AFE) Ceramic material, such as lead zirconate titanate (Pb(Zr, Ti)O 3) system, silver citrate (AgNbO) 3Etc., the use of electric field-induced antiferroelectric-ferroelectric phase transition is considered to be an effective method to increase the energy density of dielectric materials. However, high energy loss (inefficient) and poor correlation with antiferroelectric-ferroelectric phase transition Reliability is the main problem limiting the application of antiferroelectric ceramics.
Recently, Associate Professor Li Fei, Professor of the School of Telecommunications of Xi'an Jiaotong University, directed the students, at (Na 0.5Bi 0.5TiO 3-(Sr 0.7Bi 0.2TiO 3 (NBT-SBT) system Lead-free dielectric ceramics simultaneously achieve high energy storage density and energy storage efficiency. The main principle is to use the A-site heterovalent cation to destroy the long-range order of the anti-ferroelectric material dipole, and achieve anti-iron The structure of the electrical material on the nanometer scale is not uniform, which reduces the hysteresis of the polarization relative to the electric field, thereby improving the energy storage efficiency of the material. Based on the NBT-SBT system, the research group used the casting process to prepare a multilayer ceramic capacitor (MLCC). , its energy storage density and efficiency reached 9.5Jcm respectively -3And 92%. At the same time, the capacitor exhibits good stability in the range of -60~120 °C, the storage density change rate is less than 10%, and the device storage density decreases by only 8% after charging and discharging 1 million times. The characteristics indicate that NBT-SBT multilayer ceramic capacitors are expected to be used in high energy energy storage.
Left: SEM photograph of cross section of NBT-SBT multilayer ceramic capacitor, right: Experimental test results of energy storage characteristics of NBT-SBT multilayer ceramic capacitor, fatigue test results
The research results have been published online in Advanced Materials (IF=21.95), a well-known journal in the field of materials science. Li Jinglei, Ph.D. student of the Key Laboratory of Electronic Ceramics and Devices of the Ministry of Education, Xi'an Jiaotong University, is the first author of this article, Associate Professor Li Fei and Australia. Professor Zhang Shujun of the University of Wollongong is the co-author of this article. Xi'an Jiaotong University is the first author of this article. This is another high-level article published by Professor Xu Zhuo in the past after Nature Materials, Nature Communications, Advanced Functional Materials. It marks that Xi'an Jiaotong University is at the international leading level in the research of dielectric energy storage.
The work was supported by the National Natural Science Foundation of China, the '111 Initiative' (B14040) and other projects.
