Nanofiber-reinforced polymer nanocomposite with hierarchical interfaces for high-temperature dielectric energy storage applications

Abstract

Flexible polymer nanocomposites reinforced by high-dielectric-constant ceramic nanofillers have shown great potential for dielectric energy storage applications in advanced electronic and electrical systems. However, it remains a challenge to improve their energy density and energy efficiency at high temperatures above 150°C. Here, we report a nanofiber-reinforced polyetherimide nanocomposite employing BN-BaTiO 3 heterogeneous nanofibers as fillers, where the BN nanoparticles were embedded inside BaTiO 3 nanofibers to create BN/BaTiO 3 /PEI hierarchical interfaces. The high dielectric constant and the geometric large aspect ratio of the BN-BaTiO 3 heterogeneous nanofibers lead to simultaneously increased dielectric constant and breakdown strength of the nanocomposite over a broad temperature range. In particular, the emerging hierarchical BN/BaTiO 3 /PEI interfaces enable promoted density and energy level of traps for the mobile charges, which further suppresses the conduction loss and improves the breakdown strength under high temperatures, as confirmed by a combination of thermally stimulated depolarization current measurement and phase-field simulation.Finally, the nanocomposite with hierarchical interfaces boosts an ultrahigh energy density of 5.23 J cm −3 with an energy efficiency of > 90% at 150°C, which is the highest energy density reported so far in nanofiber-reinforced polymer nanocomposites and also outperforms most nanocomposites counterparts dispersed with nanoparticles and nanosheets. Our work demonstrates hierarchical interface engineering as an effective strategy to promote the high-temperature energy storage performance of fiber-reinforced polymer nanocomposites, which is of significance for their applications in high-temperature harsh conditions.

All-organic ArPTU/PEI composite dielectric films with high-temperature resistance and high energy-storage density

“…At 25 °C, the maximum U e (5.75 J cm −3 at 600 MV m −1 ) of the composite film was 44% higher than that of the original PEI (4.0 J cm −3 at 500 MV m −1 ), and the efficiency could be maintained above 97%. In addition, at 580 MV m −1 and 150 °C, the PEI/2 wt% ArPTU composite film showed an ultra-high U e of 5.34 J cm −3 , exceeding that of many high-temperature dielectric polymers (such as PI, PEI, PEEK, and PMMA) and PEI-based nanocomposites, 14,35–38 as shown in Fig. 4d.…”

Enhanced energy density and efficiency of all-organic composites by designing a multilayer gradient structure

“…2,8 In recent years, some typical feasible strategies have been adopted to improve the breakdown strength and polarization of dielectrics, including microstructural design and modification of polymer molecular chains, 9–14 polymer blends, 15–18 and the construction of organic/inorganic composites. 19–22 For example, He et al prepared PMMA based random copolymer films, block copolymer films and blend films, respectively, and explored the effects of the sequential structure, phase separation structure, and modification method on the energy storage performance of PMMA based dielectrics. Due to the suppression of electron injection and charge transfer by the strong electrostatic attraction of π-conjugated benzophenanthrene groups, the discharge energy density of PMMA based random copolymer films reaches 15.00 J cm −3 with an energy efficiency of 80% at 872 kV mm −1 .…”