Enhanced performance in multilayer-structured nanocomposites using BaTiO3 and Ba0.8Sr0.2TiO3 decorated graphene hybrids

It is challenging to achieve high energy density in conductive fillers/polymer nanocomposites due to their extremely low breakdown strength. In this paper, a novel multi-component and multilayer-structured nano composite was designed and investigated, consisting of Ba0.8Sr0.2TiO3 decorated graphene (BST @ RGO)/poly (vinylidene fluoride-chlorotrifluoroethylene) copolymer (P(VDF-CTFE)) composites (R-Layer) as interlayer, and BaTiO3/P(VDF-CTFE) composites (B-Layer) as surface layer. The multilayer-structured nanocomposites were prepared through layer-by-layer solution casting method. Enhanced breakdown strength, energy density, dielectric constant and low dielectric loss were simultaneously obtained in the nanocomposites by the multilayer structure. The maximum dielectric constant of the composites with multi-layered structure was approximately 14, which was increased by 16.67% compared to the pure P(VDF-CTPE) layer, and the dielectric loss was as low as 0.047 at 1 kHz, even lower than pure P(VDF-CTFE) in frequency range from 10 kHz to 1 MHz. The breakdown strength and energy storage density of BRB-3 nanocomposites with 3 R-Layers reached to 220 kV mm(-1) and 6.49 J cm(-3),respectively. These results demonstrated that designing multi-component and multilayer-structured nanocomposites was an effective approach to fabricate high performance dielectric nanocomposites.