Achieving high comprehensive energy storage properties of BNT-based ceramics via multiscale regulation

Abstract

It is difficult to obtain high polarization strength and high breakdown strength synchronously, resulting in the drawback of lower energy storage density, which inhibits commercial application of energy storage materials. We have successfully prepared (1-x)(0.93Bi0.5Na0.5TiO3-0.07CaSnO3)-xSrTiO3 (BNT–CS–xST) ceramics by solid-state method. The presence of polymorphic nanodomains and the large electric displacement generated by the high charge Sr2+-Sr2+ ion pairs help to delay saturation polarization (Pm ∼ 48.64 μC/cm2 at 315 kV/cm). In addition, the breakdown field strength (Eb) is increased by grain refinement and increasing the band gap. It is noteworthy that a high recoverable energy storage density (Wrec = 4.2 J/cm3) and a great efficiency (η = 88%) were achieved simultaneously in BNT–CS–0.5ST ceramic. Moreover, excellent charge-discharge performance was also achieved, with a discharge energy density Wd of 2.2 J/cm3, a current density CD of 1724 A/cm2 and a power density PD of 250 MW/cm3. The study demonstrates that the great potential of BNT–CS–xST ceramics in power storage devices and provides an effective strategy for designing ceramics dielectric capacitors with excellent performance.