Design of Lead-Free Films with High Energy Storage Performance via Inserting a Single Perovskite into Bi₄Ti₃O₁₂

We report a distinctive way for designing lead-free films with high energy storage performance. By inserting different single perovskite cells into Bi₄Ti₃O₁₂, P–E hysteresis loops present larger maximum polarization, higher breakdown strength and smaller slim-shaped area. We prepared 0.15Bi₇Fe₃Ti₃O₂₁-0.5Bi₄Sr₃Ti₆O₂₁-0.35Bi₄Ba₃Ti₆O₂₁ solid solution ferroelectric films employing the sol-gel method, and obtained high energy storage density of 132.5 J/cm³ and efficiency of 78.6% while maintaining large maximum polarization of 112.3 μC/cm² and a high breakdown electric field of 3700 kV/cm. Moreover, the energy storage density and efficiency exhibit stability over the temperature range from 20 °C to 125 °C, and anti-fatigue stability maintains up to 10⁸ cycles. The films with a simple preparation method and high energy storage performance are likely to become candidates for high-performance energy storage materials. (paper)