Latest Designing Principle on the Microstructure and Lattice-Structure for High-Energy-Density Antiferroelectric Materials in Fast Discharging Applications

Antiferroelectric (AFE) materials are considered to have a potentially ultrahigh energy density, which is a determinant for pulse capacitors used in the energy storage section of fast discharging applications. Optimization of the energy density in AFE materials has basically focused on the modulation of compositions or microstructure according to some empirical principles. An efficient, targeted, and in-depth designing strategy is always expected based on some distinct structure–property relationships. In this work, we investigated an AFE material, La-doped Pb(Yb1/2Nb1/2)0.92Ti0.08O3, summarizing two effective designing criteria from the microstructure to lattice-structure: (1) Introducing the secondary phase, featuring slightly lower permittivity but higher resistivity, is conducive to breakdown strength EB and energy density. The measurement of TEM, XRD, SEM, and the complex impedance spectrum proves that the introduced inhomogeneous phase redistributed the local electric field and improved EB based on the Poisson electrostatic equation. (2) Modulating the primitive cell to that with a larger cpc/apc ratio intensified [BO6] tilting, and a weakened [BO6] distortion leads to the stabilized AFE phase, subsequently enhancing the energy density. This is verified in the energy landscape of the different lattice-structure by density functional theory (DFT) calculation. On the basis of the two criteria, this work greatly enhances the recoverable energy density to 8.22 J cm–3 under an ultrahigh 49.2 kV mm–1 electric field, superior to most alternatives of dielectric energy storage materials. This work initially establishes effective designing criteria from the microscale to lattice scale instead of empirical compositional design, expected to contribute to further explorations on fundamental structure–property relationships for AFE energy storage materials.