High energy storage performance in (Bi_0.4Na_0.2K_0.2Ba_0.2)TiO₃-Bi(Zn_2/3Ta_1/3)O₃ high-entropy ceramics with excellent temperature and frequency stability

Dielectric capacitors with high power density, cost-effectiveness, and harsh environmental working abilities have gained considerable research attention. Dielectric materials are key components of dielectric capacitors and directly influence their operational performance. Among others, high-entropy perovskites are emerging as attractive candidates for energy storage materials owing to their exceptional performance driven by the high-entropy effect. Here, a high-entropy (1-x)(Bi_0.4Na_0.2K_0.2Ba_0.2)TiO₃-xBi(Zn_2/3Ta_1/3)O₃ system for energy storage devices was designed. A systematic study was conducted to investigate the ferroelectric and dielectric properties of BNKBT-BZT high-entropy ceramics (HECs). The resultant sample exhibits strong relaxor properties and exceptional energy storage properties, with a high recoverable energy storage density (W_rec) of 4.11 J/cm³ and an energy storage efficiency (η) of 84 % under an electric field of 260 kV/cm. More interestingly, the BNKBT-15BZT HECs also display outstanding thermal and frequency stability. These findings suggest that the resultant BNKBT-15BZT HECs are highly promising for applications in dielectric energy storage within low-to-moderate electric field ranges.