Enhanced Breakdown Strength of Ferroelectric Polymer Films for Capacitive Energy Storage by Incorporating Oriented Fluorographene

Abstract

Ever-increasing electrification scenarios call for high energy density (U e) polymer nanodielectric films beyond the commercial benchmark biaxially oriented polypropylene. Ferroelectric polymers of intrinsic high dielectric constant εr, if integrated with improved breakdown strength (E b) and dielectric loss from nanofillers, would be a promising paradigm for high-U e polymer nanodielectrics. Yet, this expectation is still in its infancy because of the great challenge of increasing the E b and needs introduction of new approaches. Here, fluorographene (FG), as a young halogen derivative of graphene, is employed as an emerging nanofiller to develop high-E b polymer nanodielectrics. A dramatically enhanced E b, which is 39.4% higher than that of a neat polymer film from casting, is achieved in a composite film along with a reduced dielectric loss by incorporating only 0.2 wt % FG with in-plane orientation from electrospinning. The origin of such a high E b-reinforcing effect of FG is traced by both experimental characterizations and phase-field simulation. It is found that the in-plane oriented FG of appropriate loading level would induce both the favorable low crystallinity of the polymer matrix and the FG–polymer interface with deep traps and less defects. This, together with the high out-of-plane insulation of FG from a high fluorine/carbon ratio, regulates the charge behaviors and breakdown paths and thus significantly enhances the voltage endurance of composite films. The results demonstrate the remarkable E b-reinforcing effect of emerging FG fillers in polymer nanodielectrics and offer a strategy toward high-E b/high-U e flexible dielectric capacitors.

Self-Assembled MXene@Fluorographene Hybrid for High Dielectric Constant and Low Loss Ferroelectric Polymer Composite Films

“…As for FG, the peak located at about 14°can be indexed as the (001) reflection in a hexagonal system compound with a high fluorine content, while the one located at 41°is assigned to the (100) reflection. 43 When it comes to FMX@FG, both the characteristic peaks for FMX and FG are observable without significant changes, indicating that the original structure of FMX is preserved during self-assembly modification. This is of critical importance for FMX@FG regarding its high performance in accessing the high-ε r percolative composite, as discussed later.…”

“…The hidden diffraction peak at 20.5°is ascribed to the combined result of the ( 110) and ( 200) planes of the βphase. 43,55 Although FMX may induce some decrease in the χ c at low loading level, it can generate high β-phase proportion above 75% in the crystalline composite films. A higher β-phase is beneficial for a higher dielectric constant, 4,56 because the βphase is the one with the highest polarization per unit cell that is contributed to the alignment of all its dipoles in the same direction normal to the chain axis.…”

Reduced Polyaniline-Modified NaNbO3 Nanowire/Polyetherimide Nanocomposites for Dielectric Capacitors with Enhanced Dielectric Properties and High Thermal Stability

“…Due to the rapid development of highly miniaturized electronic devices that require more film capacitors with millisecond charging/discharging capacity, there is a great need for high-energy-storage-density polymer film capacitors. − As a core component of a dielectric capacitor, dielectric materials are also required with stable operation capacity in extreme environments for an electromagnetic energy storage system. − Therefore, polymer film capacitors should be concurrently endowed with high E b , low dielectric loss, and excellent processing characteristics. − …”

Antiferroelectric AgNbO3@KH550 Doped PVDF/PMMA Composites with High Energy Storage Performance

“…Dielectric electrostatic capacitors have become key components for power equipment and power electronic devices due to their fast charge-discharge rate and high reliability. [1][2][3][4][5] Compared with energy storage devices such as batteries and supercapacitors, dielectric capacitors have faster charging and discharging efficiency, higher power density, and can meet the requirements of miniaturization, lightweight design, and high voltage levels. [6,7] Therefore, the research and development of dielectric capacitors with high energy storage density have become a focal point in the field of electrical engineering.…”