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 with irreplaceable applications. Related devices and products are developing in the direction of miniaturization, light weight and multi-function, which puts forward higher requirements on the energy storage density of devices, and the key to improving the energy storage characteristics of devices lies in the development of dielectric materials with high energy storage density. Application of antiferroelectric (AFE) ceramic materials, such as lead zirconate titanate (Pb (Zr, Ti) O3) system, silver niobate (AgNbO3), etc., using electric field-induced antiferroelectric-ferroelectric phase transition is considered to be an improvement An effective method for the energy density of dielectric materials. However, the high energy loss (low efficiency) and poor reliability associated with the antiferroelectric-ferroelectric phase transition are the main problems that limit the application of antiferroelectric ceramics.
Recently, Associate Professor Li Fei from the Xu Xu Zhuo Research Group of the School of Telecommunications of Xi'an Jiaotong University guided students to obtain a lead-free dielectric ceramic in the (Na0.5Bi0.5) TiO3- (Sr0.7Bi0.2) TiO3 (NBT-SBT) system. 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 antiferroelectric material dipole, to achieve the non-uniform structure of the antiferroelectric material on the nanometer scale, reduce the lag of the polarization intensity relative to the electric field, and thus improve The energy storage efficiency of the material. Based on the NBT-SBT system, the research team prepared a multilayer ceramic capacitor (MLCC) using a casting process. Its energy storage density and efficiency reached 9.5Jcm-3 and 92%, respectively. At the same time, the capacitor showed good stability in the range of -60 ~ 120 ℃, the change rate of energy storage density was less than 10%, and the device energy storage density dropped only 8% after charging and discharging 1 million times. These characteristics indicate that NBT-SBT multilayer ceramic capacitors are expected to be applied in the field of high energy storage.
Left: Cross-section SEM photograph of NBT-SBT multilayer ceramic capacitor. Right: NBT-SBT multilayer ceramic capacitor energy storage characteristic test results and fatigue test results.
The research results were published online in the famous journal Advanced Materials (IF = 21.95) in the field of materials science recently. Li Jinglei, Ph.D. student of the Key Laboratory of Electronic Ceramics and Devices of the Ministry of Education, School of Telecommunications, Xi'an Jiaotong University is the first author of this article. Associate Professor Li Fei and Professor Zhang Shujun of Wollongong University in Australia are co-corresponding authors. . This is another high-level article published in recent years by Professor Xu Zhuo's research group following Nature Materials, Nature Communications, Advanced Functional Materials, which marks that Xi'an Jiaotong University is at the international leading level in dielectric energy storage research.
This work was supported by projects such as the National Natural Science Foundation of China and the "111 Introducing Intelligence Program" (B14040).
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