High-Energy-Density All-Organic Dielectric Film via a Continuous Preparation Processing

Dielectric polymers with high power density and breakdown strength (E-b) are indispensably used in electrostatic energy-storing systems and devices. However, the discharged energy density (U-e) of dielectric polymers is severely limited due to the relatively low dielectric constant (K). Although current polymer composites improve K, this approach usually faces challenges in enhancing U-e due to the trade-off relation between K and E-b and difficulties in scalable production of dielectric films. Here, a fully melt-extrudable, meter-scale, and high-U-e ferroelectric polymer-based all organic composite film comprising a poly(p-phenylene terephthalamide)-based fluxible polymer (denoted as f-PPTA) is reported. The polymer composite with only 2 wt% of f-PPTA presents a productivity of 12 m(2) h(-1) and an ultrahigh U-e of 20.7 J cm(-3), which outperforms other extruded dielectric polymers reported in the literatures. Such enhancements of dielectric and capacitive properties have been comprehensively investigated and attributed to the crystallization behavior modulations and conformation changes induced by f-PPTA. As a demonstration of real applications, the dielectric capacitors established based on the extruded films enable tens of times higher efficacy on powering electronic devices than biaxially oriented polypropylene capacitors, in addition to long-term cyclic stability. This study opens up new avenue for the design and fabrication of high-U-e polymer dielectrics that are totally compatible with industrial production.