Giant electrical energy storage density in the P(VDF-TrFE)–graphene oxide composite papers with quasi-two-dimensional ferroelectricity

The nanocomposites consisting of graphene oxide (GO) and ferroelectric copolymer poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] have been successfully synthesized by a co-evaporation method. The structural, dielectric and ferroelectric properties of the composite papers are investigated. The Raman spectroscopy analyses on the nanocomposites GO/P(VDF-TrFE) reveal that the defects in GOs are reduced significantly by the loading of ferroelectric P(VDF-TrFE). The I_G/I_D ratio increases from 1.02 (for pure GO) to 1.17 [for GO/P(VDF-TrFE)-10%], revealing that the defects are reduced by the introduction of the nano-fillers due to a strong interaction between GO and P(VDF-TrFE) in the nanocomposites. The permittivity of the nanocomposites is enhanced by almost 3-times as compared to that of the pristine GOs. The nanocomposites show a notably raised polarization with high applied electric field. Furthermore, due to the high dielectric constants, the electrical energy storage density of the nanocomposites is as high as ~ 39.89 J cm⁻³ at 2.8 MV cm⁻¹. The large energy density and high dielectric break down strength suggest that GO/P(VDF-TrFE) could be the promising novel materials for electrical energy storage.