Modulating Polarization and Carrier Migration Characteristics Via Constructing Sandwich-Structured Heterojunction Interfaces for Achieving Excellent High-Temperature Energy Storage Properties in Polymer Nanocomposites

Abstract

Dielectric polymer nanocomposites are ideal choices for electrostatic energy storage by reason of their high power density and reliability, but they do not operate efficiently at high temperatures. To solve this issue, herein, we designed and developed sandwich-structured montmorillonite (MMT)/polyetherimide (PEI)-(Pb,La)(Zr,Sn,Ti)O3 (PLZST) antiferroelectric (AFEs)@dopamine (DA)-MMT/PEI nanocomposites. On one hand, compared to current wide-band gap fillers, i.e., TiO2, Al2O3, ZrO2, and MgO, two-dimensional MMT nanosheets possess unique electrically insulating performances along the thickness direction, and thus can effectively stop charges injecting and migrating, causing low conduction loss, and large breakdown strength (Eb). On the other hand, PLZST AFEs with orthorhombic structure can exhibit high maximum electric displacement (Dmax) and small remnant electric displacement (Dr) at high temperature, which is beneficial for achieving large Dmax-Dr in the nanocomposites. In addition, large dielectric constant differences between MMT/PEI and PLZST@DA/PEI layers inhibit electrical tree growth, resulting in further raised Eb. Finite element simulations on electrical tree evolving confirm experimental breakdown results. The sandwich-structured nanocomposite exhibits impressive high-temperature (150 °C) capacitive performances possessing meanwhile a high Eb of 5265.9 kV/cm, large Ue of 7.1 J/cm3, being about 6 times that of the BOPP, and large η of 81.6%, which exceeds obviously latest polymer and polymer composites in terms of overall energy storage performances. More encouragingly, it displays an ultrahigh power density of 15.63 MW/cm3 and ultrafast discharge rate of 19.2 ns at 150 °C, indicate its excellent application potential in high-temperature pulse power systems.

Keywords: PLZST antiferroelectrics, MMT nanosheets, Sandwich-structured nanocomposites, High temperature, energy storage