Low-field energy storage enhancement in ferroelectric/paraelectric PbTiO3/SrTiO3 nanocomposites near antiferroelectric–ferroelectric transition region

Abstract

Dielectric capacitors are increasingly recognized as critical components for energy storage, particularly for integrated, portable devices that demand high energy storage density and efficiency at low operating electric fields. The conventional method for increasing energy storage capacity involves polarization engineering through chemical alterations. In this study, we propose a new approach based on domain engineering by exploiting polarization vortices embedded in a paraelectric matrix. Through phase-field simulations, we demonstrate the stabilization of vortex polar structures in 0–3 PbTiO3/SrTiO3 (PTO/STO) nanocomposites. Interestingly, switching dynamics in the nanocomposites vary with changes in PTO volume fraction, resulting in paraelectric-, antiferroelectric- and ferroelectric-like polarization behaviors. The unexpected emergence of an antiferroelectric-like behavior, characterized by double hysteresis loops, is noteworthy as the component materials are not antiferroelectric. By introducing a PTO volume fraction of 0.35, an impressive discharge energy density (DED) of 2.03 J/cm3 and a high efficiency of more than 90% can be achieved in PTO/STO nanocomposites. Notably, the DED in the PTO/STO nanocomposite is 3.42 and 1.57 times higher than that of the PTO and STO component materials, respectively. The DED enhancement is attributed to the antiferroelectric–ferroelectric transition, where the high maximum polarization and eliminated remnant polarization are obtained. Additionally, the PTO/STO nanocomposite with a PTO volume fraction of 0.35 exhibits excellent thermal stability in DED over a wide temperature range of 0–300 °C. These superior properties can also be achievable in other ferroelectric/paraelectric nanocomposites. Our study offers a new avenue for enhancing energy storage capacity through the manipulation of polar topologies and polarization characteristics.

Keywords

• Energy storage property
• Low electric field
• Ferroelectric-paraelectric nanocomposite
• Phase transition
• Phase-field model