High energy density and efficiency in all-organic P(VDF-TrFE-CFE)/PMMA dielectric films enabled by dipolar interaction and γ-irradiation

Abstract

Polymer dielectrics are promising materials for electrostatic capacitors because of their high dielectric strength and fast charge-discharge capability. However, improving the energy-storage density of fluorinated ferroelectric polymers remains challenging because enhanced polarization is often accompanied by reduced breakdown strength. In this work, all-organic poly(vinylidene fluoride- trifluoroethylene-chlorofluoroethylene)/poly(methyl methacrylate) [P(VDF-TrFE-CFE)/PMMA] dielectric films are prepared by solution blending and casting. By tuning the blend ratio, the intermolecular interactions and crystallization behavior of the films are systematically regulated, resulting in distinct changes in their electrical properties. The results suggest that dipolar interactions between PMMA carbonyl groups and polar groups in P(VDF-TrFE-CFE) disturb chain packing and suppress crystallization, thereby reducing dielectric loss and improving breakdown stability. At the optimized composition, the P(VDF-TrFE-CFE)/PMMA (50/50 wt.%) film delivers a dischaged energy density of 17.12 J/cm³ with an energy-storage efficiency of 88.11%. Further γ-irradiation of the optimized film at doses of 10-150 kGy leads to additional improvement in dielectric energy-storage performance. These results demonstrate that regulating intermolecular interactions and crystalline morphology through all-organic blending and irradiation is an effective strategy for developing high-performance polymer dielectrics.

Keywords

P(VDF-TrFE-CFE)/PMMA / dipolar interaction / γ-irradiation / dielectric energy storage / energy density and efficiency

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