Effectively boosted energy density in polymer/ceramic composites through area electron scattering and micro-regional electric displacement bridging

Dielectric electrostatic capacitors have drawn numerous attention due to the long service time and rapid charge-discharge rate. However, the enhancement of energy density is a significant challenge for elevating the energy capacity. Here, a polyvinylidene fluoride (PVDF) composite hybridly filled with anatase TiO 2 1D nanowires and 2D nanosheets is investigated which possesses a high energy density. In the composite, electric displacement and breakdown strength are increased simultaneously via a synergetic effect of nanofillers with different dimensions. At the TiO 2 loading of 8 vol% with the nanosheet/nanowire volume ratio of 5:1, the composite possesses a high E b of 610.2 MV/m, realizing 39% enhancement from 440.3 MV/m of PVDF. A high D of 12.3 μC/cm 2 , superhigh energy density of 18 J/cm 3 with high efficiency of 63% are also achieved in the composite at 600 MV/m, the displacement and energy density are higher than PVDF and its composites filled with pure 1D or 2D TiO 2 nanofillers. The mechanism of the superior energy storage properties of the composite lies in micro-regional bridging of high electric displacement by nanowires and effective area electron scattering by large-area nanosheets. Thus, this study provides a method to prepare polymer/ceramic composites with superior electric properties for high-power energy storage device applications.