High energy storage density of conductive filler composites at low electric fields through sandwich design

It is difficult to achieve high energy storage density in a low electric field by blending conductive filler composites. Sandwich structure composites with conductive filler were prepared by tape casting. The MXene/PVDF film with a thin thickness was used as two outer layers to enhance the permittivity of the composites. The BN/PVDF film with a thicker thickness was used as the intermediate layer. The growth of electrical trees in the direction of composite thickness is inhibited by interface barrier and high breakdown BN network, which plays a role in protecting the breakdown strength. The results showed that the larger energy storage density (13 J/cm 3 ) is obtained under the low electric field (360 kV/mm) when the MXene content was 0.03 vol%.