Achieving ultrahigh energy storage density and efficiency in 0.90NaNbO3–0.10BaTiO3 ceramics via a composition modification strategy

Ceramic capacitors feature great power density, fast charge/discharge rates, and excellent thermal stability. The poor energy storage density of ceramic capacitors, on the other hand, significantly limits their application in power systems. In this work, a high recoverable energy storage density of Wrec = 2.68 J cm−3 and an ultrahigh efficiency of η = 90% are simultaneously achieved in the 0.90NaNbO3–0.10BaTiO3 ceramic by doping (Bi0.7La0.3)(Mg0.67Ta0.33)O3 (NNBT–xBLMT). Due to its high bandgap, the NNBT–0.10BLMT ceramic has a large dielectric breakdown strength (BDS) of 414 kV cm−1, consistent with the first-principles calculation based on density functional theory (DFT). Moreover, the NNBT–0.10BLMT ceramic exhibits excellent charge/discharge characteristics, with an ultrahigh current density CD of 526.06 A cm−2 and a high power density PD of 52.61 MW cm−3. In particular, the NNBT–0.10BLMT ceramic exhibits an outstanding temperature (20 °C–110 °C), frequency (10 Hz–120 Hz), and cycling (104 cycles) stability, highlighting its application potential in MLCCs.