Giant dielectric breakdown strength together with ultrahigh energy density in ferroelectric bulk ceramics via layer-by-layer engineering

Designing of high breakdown strength and high energy density dielectric ceramics is an important but challenging issue in applications of energy-storage devices. In this work, BaTiO 3 @3 wt% Al 2 O 3 , 1 wt% SiO 2 (BTAS) and 0.87BaTiO 3 -0.13Bi(Zn 2/3 (Nb 0.85 Ta 0.15 ) 1/3 )O 3 (BTBZNT) ferroelectric ceramics are layer-by-layer designed and fabricated via isostatic lamination with the help of the Roll-to-Roll tape-casting technique. The relaxor ferroelectric BTBZNT ceramic is known for its high energy efficiency while the BTAS ceramic exhibits a higher breakdown strength. By combining their complementary advantages and the interfacial effect, a record-high dielectric breakdown strength of 790 kV cm −1 is obtained in layer-by-layer structured bulk ceramics when four BTBZNT layers and four BTAS layers alternately arrange in parallel. The corresponding discharge energy density is 5.04 J cm −3 , which is obviously much higher than that of BaTiO 3 -based ceramics (∼1–2 J cm −3 ). The mechanism by which the layer-by-layer structure can induce giant dielectric breakdown strength is studied via interface microstructure characterization and a phase-field breakdown model. In addition, the layer-by-layer structured ceramic shows an excellent temperature stability in the energy-storage performance. Under an applied electric field of 400 kV cm −1 at 1 Hz, the variation of discharge energy density is less than ±5% over the temperature range from 25 °C to 170 °C. All these features indicate that this kind of layer-by-layer structured ceramic can be considered a promising candidate in high-voltage high-temperature energy-storage systems.