@article{Wang2024, 
author = {Yan Wang and Lili Zhao and Ruicong Chen and Wenhui Zhao and Dengwei Hu and Haoran Wang and Bin Cui},
title = {Gradient-structure-enhanced dielectric energy storage performance of flexible nanocomposites containing controlled preparation of defective TiO2 and ferroelectric KNbO3 nanosheets},
year = {2024},
journal = {Nano Research},
volume = {17},
number = {5},
pages = {4079-4088},
keywords = {energy density, dielectric, two-dimensional, oxygen vacancies, breakdown strength, asymmetric trilayered structure},
url = {https://www.sciopen.com/article/10.1007/s12274-023-6308-4},
doi = {10.1007/s12274-023-6308-4},
abstract = {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 KNbO3 (KN) and TiO2 (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 (Eb) and the composite energy density (Ue). 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 Eb 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.}
}