Enhanced comprehensive energy storage performance of BNST-based lead-free ceramics with innovative BLZT addition

Lead-free relaxor ferroelectric energy-storage ceramics based on Bi_0.5Na_0.5TiO₃ (BNT) systems are renowned for their exceptional properties, including a high P_max (>40 μC/cm²) and Curie temperature (T_c ∼ 320 °C). In the pursuit of further enhancing their energy storage characteristics, we have developed a novel series of ceramics, namely (1-x)(Bi_0.5Na_0.5)_0.7Sr_0.3TiO₃-xBa_0.94La_0.04Zr_0.02Ti_0.98O₃ (x = 0, 0.1, 0.2, 0.3 and 0.4), abbreviated as (1-x)BNST-xBLZT, and assessed its structural and performance attributes. With the introduction of Ba_0.94La_0.04Zr_0.02Ti_0.98O₃(BLZT), these ceramics retain their characteristic phase structure where tetragonal (T) and rhombohedral (R) phases coexist, effectively disrupting long-range ordered domains and augmenting their energy storage capabilities. Notably, we achieved a remarkable recoverable energy storage density (W_rec) of 3.41 J/cm³ and an extraordinarily high energy storage efficiency (ƞ) of 87.33 % in ceramics with x = 0.3 under an electric field of 260 kV/cm. Furthermore, these ceramics exhibit excellent temperature stability (−2 °C ∼ 228 °C), robust cycle stability (10⁶ cycles), a substantial discharge energy density (W_d ∼ 0.93 J/cm³), impressive power density (P_D ∼ 39.3 MW/cm³), and rapid transient discharge times (t_0.9 ∼ 0.14 μs). In summary, the 0.7BNST-0.3BLZT ceramic demonstrates high power density, rapid charge and discharge rates, and excellent temperature and cyclic stability, positioning it as a promising material for pulse power systems and harsh environments.