Gradient-structure-enhanced dielectric energy storage performance of flexible nanocomposites containing controlled preparation of defective TiO_(2) and ferroelectric KNbO_(3) nanosheets  

作　　者：Yan Wang Lili Zhao Ruicong Chen Wenhui Zhao Dengwei Hu Haoran Wang Bin Cui 

机构地区：[1]Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education Shaanxi Key Laboratory of Physico–Inorganic Chemistry,Xi’an Key Laboratory of Functional Supramolecular Structure and Materials,College of Chemistry and Materials Science,Northwest University,Xi’an 710127,China [2]School of Information Science and Technology,Northwest University,Xi’an 710127,China [3]Engineering Research Center for Titanium Based Functional Materials and Devices in Universities of Shaanxi Province,Faculty of Chemistry and Chemical Engineering,Baoji University of Arts and Sciences,Baoji 721013,China

出　　处：《Nano Research》2024年第5期4079-4088,共10页纳米研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.21071115);the Shaanxi Province Natural Science Foundation Research Project(Nos.2020JZ–44 and 2021JZ–44);the Key Science and Technology Innovation Team of Shaanxi Province(No.2019TD–007);Northwest University 2023 college students innovation and entrepreneurship training program project(No.2023354).

摘　　要：Next generation power system needs dielectrics with increased dielectric energy density.However,the low energy density of dielectrics limits their development.Here,an asymmetric trilayered nanocomposite,with a transition layer(TL),an insulation layer(IL),and a polarization layer(PL),is designed based on poly(vinylidene fluoride)-polymethyl methacrylate(PVDF-PMMA)matrix using KNbO_(3)(KN)and TiO_(2)(TO)as the nanofillers.The morphology and defect control of the two-dimensional nano KN and nano TO fillers are realized via a hydrothermal method to increase the composite breakdown strength(E_(b))and the composite energy density(U_(e)).The asymmetric trilayered structure leads to a gradient electric field distribution,and the KN and TO nanosheets block charges transfer along z direction.As a result,the development path of the electrical trees is greatly curved,and E_(b) is effectively improved.And the Ue value of the nanocomposites reaches 17.79 J·cm^(-3) at 523 MV·m^(-1).On the basis,the composite Ue is further improved by defect control in TO nanosheets.The nanocomposite KN/TO/PVDF-PMMA containing TO with less oxygen vacancy concentration(calcined at oxygen atmosphere)acquires a high Ue of 21.61 J·cm^(-3) at 548 MV·m^(-1).This study provides an idea for improving the energy storage performance by combining the design of the composite dielectric structure and the control of nanofillers’defect and morphology.

关 键 词：asymmetric trilayered structure two-dimensional energy density oxygen vacancies breakdown strength dielectric 

分 类 号：TB33[一般工业技术—材料科学与工程]