Superior energy storage performance and ultrafast discharge of NBBT-based ceramics via introducing linear dielectric additives and rare earth oxides

Abstract

Ferroelectric ceramics have low energy storage performance due to their nearly square hysteresis loops and low dielectric breakdown strength, which affects their practical applications for high-power energy storage capacitors. Therefore, we solve this problem by introducing a linear dielectric additive and rare earth oxide into Na_0.5Bi_0.5TiO₃-based ceramics. The (1 − x)(0.94Na_0.5Bi_0.5TiO₃–0.06BaTiO₃)–xCa_0.7Sm_0.2TiO₃ [(1 − x)NBBT–xCST] ceramics were designed and prepared by the conventional solid-state reaction method. The results show that the introduction of Ca_0.7Sm_0.2TiO₃ can effectively inhibit the grain growth, optimize the relaxation behavior and improve the band gap, which are conducive to the simultaneous enhancement of energy storage density and efficiency. The reliability of the experimental results is also verified by finite element simulation (COMSOL). A high recoverable energy density (W_rec) of 5.1 J cm⁻³, a high efficiency (η) of 88% and an ultrafast discharge time of 28 ns were finally achieved in NBBT ceramics with x = 0.35. Notably, the sample exhibits superior thermal stability over a wide temperature range of 20–140 °C. These properties provide a new design approach for energy storage capacitors.