Controllable preparation of Na0.4K0.1Bi0.5TiO3–CaZrO3–NaNbO3 nanoceramics with excellent temperature-stable energy storage performance by combining sol-gel synthesis and two-step sintering

Abstract

For the development of miniaturization and integration of multilayer ceramic capacitors, superior energy storage nanoceramics with wide temperature stability should be urgently explored for practical application. Herein, a carefully controllable preparation combining sol-gel synthesis, self-assembly arrangement and two-step sintering is proposed to realize comprehensive temperature-stable energy storage in 0.95Na0.4K0.1Bi0.5TiO3-0.05CaZrO3-xNaNbO3 nanoceramics (x is the amount of NaNbO3 relative to the 0.95Na0.4K0.1Bi0.5TiO3-0.05CaZrO3). The results have proven that the particle size from powders to ceramics can be controlled by sol-gel synthesis combined with two-step sintering, thus enhancing the ceramic BDS. The self-assembled packing arrangement of binary particle size powders promotes densification. The ceramic structure is dominated by the pseudocubic phase, in which the coexistence of multiphase nanodomains, including tetragonal, rhombohedral and orthorhombic phases, is observed in the local area. The induced nanodomains are conducive to improving ΔP and ƞ and benefiting the temperature stability. Defect control can be realized by adjusting the doping concentration of Nb5+ at the B site. The Wrec value reaches 2.63 J/cm3 at x = 0.10, with a medium η of 83.5% and a wide temperature-stable dielectric performance (│Δε/ε150 °C│≤15% at 72–421 °C). Moreover, nanoceramics with x = 0.15 show the widest temperature-stable dielectric performance at 44–483 °C. Therefore, it is feasible to optimize the temperature-stable energy storage in nanoceramics through preparation optimization.