I. Introduction
In recent years, dielectric nanocomposites have attracted great attention in high-frequency, high-voltage, and high-temperature environments due to their ultrahigh power density and superior response time [1], [2], [3]. According to the calculation formula of energy storage density () of dielectrics: (where , , , and E denote discharge energy density, maximum/remnant electric displacement, and the applied electric field), both large breakdown strength () and strong electrical displacement (or high permittivity) can promote large of polymer nanocomposite. Thus, polymer/ceramics nanocomposites are promising choices due to the advantages of high resistance to penetration of polymer matrix combined with high electrical displacement of ceramic nanofillers [4], [5], [6].