High-efficiency lead-free BNT-CTT perovskite energy storage ceramics under high electric field

The energy issue is currently a highly significant topic of concern, and the development of environmentally friendly and high-performance lead-free energy storage devices is fundamental to solving energy problems, but it also poses challenges. Lead-free environmentally friendly (Bi0.5Na0.5)TiO3 [BNT] has attracted widespread attention due to its high polarization, but its low efficiency greatly affects its practical application. In this study, 1-x(Bi0.5Na0.5)TiO3-xCa(Ti0.8Ta0.16)O3 [1-xBNT-xCTT]ceramics were prepared to investigate the relationship between their microstructure and macro energy storage properties. With the introduction of CTT, the long-range order was broken, reducing the grain size; the introduction of high bandgap energy Ta2O5 reduced residual polarization and improved the energy storage efficiency of the ceramics. Finally, high energy storage (Wrec = 3.01 J/cm3) and high energy storage efficiency (ƞ = 90 %) were achieved in the 0.7BNT-0.3CTT ceramics, and the breakdown field strength was increased to 350 kV/cm, with excellent discharge performance (PD of 28.97 MW/cm3, t0.9 of 1.9 μs). This study explores lead-free relaxor ferroelectric energy storage capacitors with high efficiency under high electric fields, providing a new approach to optimize the energy storage performance of ceramic energy storage devices. •A new lead-free, environmentally friendly binary relaxor ferroelectric ceramic with Wrec = 3.01 J/cm3 and ƞ = 90 %.•The introduction of the second component reduces the grain size of the material, enhancing the Eb of the material.•The 0.7BNT-0.3CTT ceramic exhibits a excellent discharge characteristics under a 220 kV/cm electric field.