Harnessing local inhomogeneity for enhanced dielectric energy storage

Inorganic dielectric capacitors are highly demanded in pulsed systems due to their high-power output, but the low energy density limits device miniaturization. Relaxor ferroelectrics with local inhomogeneity are leading candidates for energy storage because of small hysteresis and relatively high polarization. However, the mechanism of local inhomogeneity in high-performance relaxor ferroelectrics is still not well understood due to limitations in characterization techniques and insufficient interpretation of computations. We reveal the microstructural origin of enhanced energy storage performance based on polar nanoregion and polar slush models. While smaller domains improve energy storage, more crucial factors are electrostatic interactions between polar and non-polar regions and intense disordered random fields, caused by local inhomogeneity. Combining merits of both models, we develop a framework directly relating local inhomogeneity to dielectric properties that successfully simulates solid solutions and high-entropy dielectrics. Our results can offer insights into energy storage performance in complex relaxor ferroelectrics.