Ultrahigh capacitive energy storage of high-entropy Bi_0.5Na_0.5TiO₃ ceramics via polymorphic heterogeneous polar...

Dielectric capacitors play a crucial role in storing and releasing electrical energy within modern electronic devices. However, their energy storage density is significantly constrained by the polarization (P) and breakdown strength (E_b). In this study, a unique high-entropy design strategy is proposed to fabricate the (1-x)Bi_0.47Na0.₄₇Ba_0.06TiO₃-xCa_0.7Lu_0.2Ta_0.2Zr_0.1Ti_0.65O₃ (xCLTZ, x = 0, 0.1, 0.2, 0.25, 0.30) solid solution. Atomic-scale observations indicate that locally polymorphic heterogeneous polarization structure with multiple symmetries is induced. As configuration entropy (ΔS_config) increases, the resistivity of ceramic is effectively enhanced, weakening the anisotropic field and lowering the domain switching barrier, thereby achieving simultaneous enhancement of both high breakdown strength and large polarization. Consequently, an ultra-high W_rec of 17.01 J/cm³ and large η of 84.1% were realized in the 0.25CLTZ, which also exhibits excellent temperature and frequency stability. This study systematically reveals the underlying mechanism among entropy-driven local lattice distortion, polarization configuration, and energy storage performance, thereby providing valuable insights for designing advanced dielectric materials with high entropy.