First-Principles Study of La2–xYxTi2O7 Solid Solution Antiferroelectrics for High-Efficiency Energy Storage

Abstract

As a paradigm of engineering antiferroelectric(AFE)-ferroelectric(FE) transition on rare-Earth/titanium complex oxides by solid solution to develop advanced dielectric energy storage materials with high energy density and efficiency, the La2-xYxTi2O7 solid solution antiferroelectrics are theoretically investigated by first-principles calculations of structural stability, band-structure and dielectric polarization hysteresis and AFE-FE transition energy. Dielectric energy storage performances are evaluated and explained by energy density and efficiency as well as AFE or FE phase stability under the electric fields approaching the uppermost critical value determined by electronic band-gap, which highly hinges on field-applying crystallographic orientation and Y-element content. In merit of its multiferroic properties, La2-xYxTi2O7 crystals are demonstrated to acquire energy storage performances of 35 J·cm−3 energy density and 90% efficiency for the amenable maximum electric field of 4 MV·cm−1. The present study is expected to motivate the prospective experimental studies of these potential AFE materials which have so far been rarely deliberated in energy storage applications.