Energy storage in lead-free Ba(Zr, Ti)O$_{3}$ relaxor ferroelectrics: Large densities and efficiencies and their origins

TL;DR

This study uses atomistic modeling to explore energy storage capabilities in lead-free Ba(Zr, Ti)O₃ relaxor ferroelectrics, revealing high energy densities and efficiencies influenced by temperature, strain, and electric field direction.

Contribution

The paper introduces a first-principles-based effective Hamiltonian approach to predict ultrahigh energy densities and efficiencies in Ba(Zr, Ti)O₃ relaxor ferroelectrics, along with a phenomenological model explaining these features.

Findings

Energy density increases linearly with temperature along certain directions.

Films show strain-dependent behavior of energy density at room temperature.

Achieves over 100 J/cm³ energy density with 100% efficiency.

Abstract

An atomistic first-principles-based effective Hamiltonian is used to investigate energy storage in Ba(Zr$_{0.5}$Ti$_{0.5}$)O$_{3}$ relaxor ferroelectrics, both in their bulk and epitaxial films' forms, for electric fields applied along different crystallographic directions. We find that the energy density linearly increases with temperature for electric fields applied along the pseudocubic [001], [110] and [111] directions in Ba(Zr$_{0.5}$Ti$_{0.5}$)O$_{3}$ bulk. For films at room temperature, the energy density adopts different behaviors (i.e., increase versus decrease) with strain depending on the direction of the applied electric fields. We also predicted ultrahigh energy densities (basically larger than 100 J/cm$^{3}$) with an ideal efficiency of 100\% in all these Ba(Zr$_{0.5}$Ti$_{0.5}$)O$_{3}$ systems. In addition, a phenomenological model is used to reveal the origin of all the aforementioned features, and should be applicable to other relaxor ferroelectrics.