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 SrTiO 3 @SiO 2 nanowires (ST@SiO 2 NWs) fillers are fabricated based on interface engineering for high U e . The optimized SiO 2 insulating layer could effectively confine the mobility of space charge carriers in the interfacial zone between ST NWs and thick SiO 2 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 SiO 2 coating) nanocomposite, and it is almost 2.5 times that of pure P(VDF-CTFE). 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.