Dielectric response and breakdown behavior of polymer-ceramic nanocomposites: The effect of nanoparticle distribution

Polymer-ceramic nanocomposites play an essential role in the application of pulsed power system, due to their ultrahigh power density and fast charging-discharging capability. It is very promising for them to be applied in energy storage capacitors and hybrid electric vehicles for the recent progressing in the improving energy density. The volume fraction, morphology, size, aspect ratio and distribution of ceramic particles have been reported to have significant effect on the dielectric response and breakdown strength of nanocomposites, which are two main factors that determine the energy density of nanocomposites. In this study, we introduce a quantified method to describe the distribution of ceramic nanoparticles in polymer matrix, then focus on the effect of nanoparticles distribution on dielectric response and breakdown strength of nanocomposites through finite element method and phase field method. Results indicate that the non-uniform distribution of ceramic nanoparticles will aggravate the concentration of local electric field, thus slightly enhance the dielectric response but seriously decrease the breakdown strength of nanocomposites. To verify the size effect of ceramic particles on breakdown strength of nanocomposites, three types of well distributed nanoparticles with different diameter of particles have also been calculated using the same method.