Improving the energy density of P(VDF-HFP)/boron nitride nanosheets nanocomposites by using the third phase filler with high dielectric constant

The research on film capacitors with high energy density (U-e) has attracted great attention in these years, due to their applications in modern electric system. However, the low U-e is the major limitation for decreasing the size and weight of ferroelectric film capacitors. In this research, in order to improve the breakdown strength (E-b) and dielectric constant at the same time, P(VDF-HFP) based ternary nanocomposites were prepared by using edge-hydroxyl boron nitride nanosheets (EOH-BNNSs) with high E-b and the third phase filler with high dielectric constant. Three fillers with dielectric constant from large to small, namely, barium titanate (BT), titanium dioxide (TO), alumina (AO) were added into P(VDF-HFP)/EOH-BNNSs nanocomposites, respectively. The E-b, dielectric constsnt, dielectric loss, U-e, thermal conductivities and mechanical properties of the ternary nanocomposites were thoroughly investigated. The results indicate the local electric field concentration has great influence on the E-b of ternary nanocomposites. However, with low filler loading, the synergy effect and weak local electric field concentration can not only improve the dielectric constant but also the E-b, finally achieving the best U-e. The easy preparation process and high U-e have endow the ternary nanocomposites with great potential application in film capacitors.