Prominent energy storage density and efficiency of Na_0.5Bi_0.5TiO₃‐based ceramics via multiscale amelioration strategy

Abstract

Eco‐friendly ceramic capacitors gradually become an important section of pulsed power devices. However, the synchronous realization of ultra‐high energy storage density (Wrec > 6 J/cm3) and efficiency (η > 90%) is difficult. Thus, a novel multiscale amelioration strategy in Na0.5Bi0.5TiO3‐based ceramics is proposed to achieve ultra‐high energy storage density and efficiency. The multiscale amelioration strategy for (Na0.5Bi0.47La0.03)0.94Ba0.06TiO3 (NBLBT) ceramic focuses on grain size, bandgap width, and dielectric relaxor behavior, which can be regulated by introducing Sr(Al0.5Nb0.25Ta0.25)O3 (SANT). On the one hand, the refined grain size and increased bandgap width are conducive to improving the breakdown strength. On the other hand, the optimized dielectric relaxation behavior is beneficial to suppress the remanent polarization. Accordingly, an ultrahigh Wrec = 6.89 J/cm3 and η = 90.1% are simultaneously achieved in 0.84NBLBT‐ 0.16SANT ceramic. In addition, the sample synchronously possesses excellent thermal and frequency stability (a variation within 5% in Wrec and η), transient discharge rate of t0.9 ∼ 78.8 ns and a high‐power density of PD ∼ 114.5 MW/cm3. This study provides an effective strategy to further develop pulsed power devices.