High energy storage performance for dielectric film capacitors by designing 1D SrTiO3@SiO2 nanofillers

The development of advanced dielectric film materials with high energy storage performance is of critical significance for pulsed power capacitor applications. Nevertheless, the low discharged energy density (U-e) of current dielectric film material restricts their further application. In this work, core-shell structured SrTiO3@SiO2 nanowires (ST@SiO2 NWs) fillers are fabricated based on interface engineering for high U-e. The optimized SiO2 insulating layer could effectively confine the mobility of space charge carriers in the interfacial zone between ST NWs and thick SiO2 insulating layer, thus reducing the interfacial polarization between the interface of nanofillers/polymer, which could be used to optimize the electric field strength and electric displacement of the corresponding nanocomposite. As a result, this nanocomposite film simultaneously exhibits enhanced maximum applied electric field (E-max) and (D-max-P-r) values, thus releasing an ultrahigh discharged energy density of 14.7 J/cm(3) at 390 MV/m, which is 99% higher than that of the conventional ST/P(VDF-CTFE) (without SiO2 coating) nanocomposite, and it is almost 2.5 times that of pure P(VDF-CITE). This work demonstrates the superiority of the core-shell structured paraelectric nanowire in enhancing the energy storage performance of dielectric film capacitors, which is expected to guide the design of advanced energy-storage nanocomposites.