Design of Lead-Free Films with High Energy Storage Performance via Inserting a Single Perovskite into Bi_4Ti_3O_12

We report a distinctive way for designing lead-free films with high energy storage performance. By inserting different single perovskite cells into Bi_4Ti_3O_12, P–E hysteresis loops present larger maximum polarization, higher breakdown strength and smaller slim-shaped area. We prepared 0.15Bi_7Fe_3Ti_3O_21-0.5Bi_4Sr_3Ti_6O_21-0.35Bi_4Ba_3Ti_6O_21 solid solution ferroelectric films employing the sol-gel method, and obtained high energy storage density of 132.5 J/cm^3 and efficiency of 78.6% while maintaining large maximum polarization of 112.3 μC/cm^2 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 ℃ to 125 ℃, and anti-fatigue stability maintains up to 10^8 cycles. The films with a simple preparation method and high energy storage performance are likely to become candidates for high-performance energy storage materials.