Energy storage properties of BiTi_0.5Zn_0.5O₃-Bi_0.5Na_0.5TiO₃-BaTiO₃ relaxor ferroelectrics

(1-x)BiTi_0.5Zn_0.5O₃-x(0.935Bi_0.5Na_0.5TiO₃-0.065BaTiO₃) (abbreviated as BTZx) lead-free ceramics were prepared by using a conventional solid state reaction method and their composition and temperature dependent energy-storage properties were investigated. The addition of BiTi_0.5Zn_0.5O₃ sharply decreased the content of ferroelectric phase, leading to lowered remanent polarization and coercive field. A large energy storage density (W) of 1.04 J cm⁻³ was achieved at 95 kV cm⁻¹ for BTZ0.916. In the high temperature region, the remanent polarization was suppressed, while maximum polarization still maintained at a high level. Significantly enhanced W of ~0.952 J cm⁻³ at 80 kV cm⁻¹ was obtained with a relatively high efficiency of ~0.8, making these materials attractive in energy storage applications.