Significantly enhanced energy storage density in lead-free barium strontium titanate-based ceramics through a cooperative optimization strategy

Lead-free ceramics are important in the sustainable advancement of energy storage techniques owing to their exceptional density of power, commendable resistance to high temperatures, and non-toxic nature. However, lead-free ceramics are no longer aligned with the requirements for the miniaturization and light weighting of electronic components because of their limited energy density and conversion efficiency. In this study, the storage performance of lead-free ceramics was optimized by constructing (1 − x)(Ba_0.8Sr_0.2)TiO₃-xBi(Zn_2/3Ta_1/3)O₃ ceramics using a cooperative optimization strategy. This strategy involved utilizing Bi(Zn_2/3Ta_1/3)O₃ to induce polar nano-regions, contributing to an increase in E_b and a reduction in P_r, thereby enhancing the energy storage properties. Notably, the 0.91(Ba_0.8Sr_0.2)TiO₃-0.09Bi(Zn_2/3Ta_1/3)O₃ relaxation ferroelectric ceramic demonstrated the ability to simultaneously achieve an ultra-high W_rec of 5.53 J cm⁻³ and an excellent η of 93.6% at a relatively high electric field intensity of 460 kV cm⁻¹. Furthermore, the samples exhibited a high η (∼96%) in the 5-100 Hz frequency range and in the 30-100 °C temperature range. The collective outstanding performance of the 0.91(Ba_0.8Sr_0.2)TiO₃-0.09Bi(Zn_2/3Ta_1/3)O₃ ceramic substantiates its immense potential for utilization in pulse power capacitors.