Enhanced energy‐storage properties in Zr 4+ ‐modified (Bi 0.4 Ba 0.2 K 0.2 Na 0.2 )TiO 3 high‐entropy ceramics

Recently, high‐entropy perovskite oxides (HEPOs) have received increasing interest for energy storage applications owing to their unique structure, huge composition space, and promising properties. However, designing HEPOs with improved energy storage performance remains a challenge. In this study, various HEPOs were designed by partially replacing Zr 4+ for Ti 4+ in (Bi 0.4 Ba 0.2 K 0.2 Na 0.2 )TiO 3 medium‐entropy ferroelectric ceramics. The resulting ceramics exhibited a pseudo‐cubic structure. With increasing Zr 4+ content, the ceramics gradually transformed into relaxor ferroelectrics. The energy storage performance of the ceramics depended on the Zr 4+ content. The sample with 20 mol% Zr 4+ showed the best energy storage performance with a maximum reversible energy density of 2.47 J/cm 3 and an energy storage efficiency of 82.3% at a low applied electric field (224 kV/cm). This study obtained a promising material for the new generation dielectric energy storage capacitors and provided a novel method for enhancing energy storage performance.