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

Abstract

The development of high-performance antiferroelectric ceramics/polymeric materials with great thermal stability has attracted considerable interest due to their extensive use in efficient power sources and electronic devices. Nevertheless, the high energy storage density and thermal stability of dielectrics are seriously restricted due to their poor processibility and weakened breakdown strength (E b ). To resolve these tough issues, it would be highly effective and feasible if an organically modified highaspect-ratio one-dimensional (1D) antiferroelectric ceramic can be employed. Specifically, the 1D nanofiller can extend the breakdown path and improve the local electric field distribution while the organic modification endows dielectrics with enhanced interface polarization and improved compatibility, thus yielding high energy storage density. Herein, a series of high-aspect-ratio 1D NaNbO 3 nanofiller with organic insulating reduced polyaniline (R-PANI) layer are synthesized by the oxidative polymerization and then introduced into the polyetherimide (PEI) matrix. The prepared NaNbO 3 @R-PANI/PEI nanocomposites possess enhanced dielectric constant up to 9.8 as well as ultralow dielectric loss (0.009) while maintaining the high energy density of 2.46 J/cm 3 (1.4 times of that for pure PEI) and high efficiency of 82.6% at 200 MV/m at a small loading of 3 vol %. Depending on the unique structure of the coated R-PANI, the 3 vol % NaNbO 3 @R-PANI/PEI increased the energy density up to 4.4 J/cm 3 and maintained high efficiency of 70.9% at 200 MV/m under 150 °C, therefore making it a potential candidate for polymeric dielectric materials used in extreme environments.

Nanocomposite Dielectric Films with Interphasic Response from Olefin Metathesis of Functionalized HfO2 Nanocrystals

“…Table S1 summarizes the dielectric properties of the polymer nanocomposites embedding different volume fractions of dielectric fillers prepared by different fabrication methods. ,− Most approaches described in the literature embed <40 vol % of dielectric fillers. While BaTiO 3 -poly­(furfuryl) alcohol nanocomposites embed 68 vol % of BaTiO 3 , the increase in effective dielectric constant turns out to be less than anticipated by Lichtenecker’s formula .…”

Simultaneous Inhibition of Conduction Loss and Enhancement of Polarization Intensity of Polyetherimide Dielectrics for High-Temperature Capacitive Energy Storage

“…For instance, the conductivity of currently commercialized biaxially oriented polypropylene (BOPP) films undergoes an inevitable increase of ∼3 orders of magnitude as the temperature increases from room temperature to 120 °C. − These generated conduction losses will be subsequently converted into Joule heat and eventually cause the thermal runaway of the capacitor. As a result, the discharged energy density ( U e ) of a BOPP film with a charge–discharge efficiency (η) of >90% greatly decreases from ∼4.0 to <0.5 J/cm 3 as the temperature increases from room temperature to 120 °C. − …”