Topologically distributed one-dimensional TiO2 nanofillers maximize the dielectric energy density in P(VDF-HFP) nanocomposite

Larger energy density is desirable for the nanocomposites as the potential dielectrics in energy storage capacitor. It is necessary to overcome the contradiction between dielectric permittivity and breakdown strength in the material. In this work, we combine the advantages of 1-dimensional nanofillers in a topological structured composite film, and maximize the energy density in P(VDF-HFP) nanocomposite. A two layered nanocomposite TO-A/TO-F/P(VDF-HFP) was fabricated with TO nanorods arrays (TO-A) embedded in the bottom layer and TO nanofibers (TO-F) contained in the top layer. The dielectric permittivity is 18.2 at 1 kHz, and the breakdown strength is 489.9 MV/m in TO-A/TO-F/P(VDF-HFP), which are much higher than that of the contrasted nanocomposites. Phase-filed simulation was adopted to demonstrate the mechanism of compatible improvement on the dielectric permittivity and breakdown strength in the nanocomposite by TO-A and TO-F, respectively. The TO-A/TO-F/P(VDF-HFP) nanocomposite film represents excellent energy storage performance 18.3 J/cm3 at 490 MV/m with efficiency of 79.7%, which is superior to other counterparts in references. This work provides new strategy to maximize the improvement of 1D nanofillers on energy storage performance in nanocomposite.