Electron-Beam Irradiation for Boosting Storage Energy Density of Tuned Poly(vinylidene fluoride-hexafluoropropylene)/Graphene Nanoplatelet Polymer Composites

Abstract

In current, the energy storage materials based on electrets and ferroelectric polymers are urgently demanded for electric power supply and renewable energy applications. The high energy storage density can be enhanced by conducting or inorganic fillers to ferroelectric polymer matrix. However, agglomeration, phase separation of fillers, interfacial phase regions and crystallinity of matrix remain the main factors for the improvement of energy storage density in those composites. Poly(vinylidene fluoride-hexafluoropropylene) was modified with graphene nanoplatelets for enhanced the dielectric properties and energy storage density, which combines the irradiated by electron beam. Tuning effect of the crystalline regions and polar phases with graphene nanoplatelets and electron irradiation on its surface, structure, electrical and energy storage properties were observed. The film homogeneity was increased by reducing the pores, along with the improvement of surface roughness and hydrophobicity, which related with the dielectric properties and energy storage density. The β-phase fraction and crystallinity improvement significantly affect electrical properties by improving polarization and dielectric constant. As a core, electron beam dramatically reduce the crystals size by two times. Hence, energy storage density of composites was enhanced, while energy loss was reduced under operating conditions. Results on the improvement of energy efficiency were from 68.11 to 74.66% for neat poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)), much higher than previously reported of 58%, and doubled for P(VDF-HFP)/GNPs composites which will be discussed and evaluated for the practical energy storage materials.