Tunable antiferroelectric-like polarization behavior and enhanced energy storage characteristics in symmetric BaTiO₃/BiFeO₃/BaTiO₃ heterostructure

The excellent energy storage performances of dielectric materials, a high energy density and efficiency, the stability in a wide range of temperature, frequency and cycling time, are surely desirable for the energy storage devices. A trade-off relationship between polarization and breakdown strength, however, limits the enhancement of energy storage properties of dielectric materials. To effectively boost the energy density and efficiency of dielectric capacitors, by inserting a BiFeO₃ layer into the BaTiO₃ film in present case, the symmetric BaTiO₃/BiFeO₃/BaTiO₃ tri-layer film heterostructure with antiferroelectric-like characteristics was constructed based on the dual-interlayer coupling effect, what's more, its antiferroelectric-like characteristics will evolve with electric field. Such the tunable polarization behavior endows it with an enhanced maximum polarization but a reduced remnant one, a delayed saturation of polarization and a high breakdown strength, which are synergistically accountable for a large energy density (W_rec~109 J/cm³) and a high efficiency (η~82.6%), together with the good thermal (T_R~200 ℃, ΔW_rec<3% & Δη<10%) and frequency (50 Hz–10 kHz, ΔW_rec<7% & Δη<13%) stabilities, particularly an outstanding cycling reliability (10⁹ cycles, both ΔW_rec and Δη<1%). Hence these findings can provide some innovative ideas for enriching the performance tuning of ferroelectrics, especially in enhancing their energy storage characteristics.