Dielectric and Energy Storage Properties of Layer-Structured Ba_n−3Bi₄Ti_nO_3n+3 (n = 4–7) Ferroelectrics

Bismuth-layered ferroelectric materials with Aurivillius structure are the potential materials for high-temperature ferroelectric materials because of their high Curie temperature and excellent ferroelectric fatigue resistance. Herein, the Aurivillius phase relaxation ferroelectrics as Ba_n−3Bi₄Ti_nO_3n+3 (n = 4–7) ceramics are studied. The layered structures are controlled by adjusting the number of BO₆ octahedrons and (Bi₂O₂)²⁺ layers. The dielectric temperature stability and voltage resistance of bismuth barium titanate ceramics are improved. The influence of composition and microstructure on their electrical properties is explored. The relationship between dielectric properties and storage properties of bismuth barium titanate ceramics and the number of layers is obtained. Ba₂Bi₄Ti₅O₁₈ ceramics show the best performance with an energy storage density of up to 1.16 J cm⁻³ and a high efficiency of ≈87.2% (under 250 kV cm⁻¹). This work provides key materials and technologies for the next generation of energy storage capacitors that can be applied in high-temperature environments as well as a new reference for the development of dielectric materials and the functional optimization of other Aurivillius phase ceramic materials.