Improving energy storage properties of NN-NBT ceramics through compositional modification

Na_0.5Bi_0.5TiO₃(NBT)-based ceramics are materials with good energy storage properties and non-ergodic relaxation ferroelectric properties, as well as high Curie temperature and good temperature stability. Herein, a new approach was devised to adjust the non-ergodic relaxation ferroelectric characteristics of Na_0.5Bi_0.5TiO₃(NBT)-based ceramics by introducing NaNbO₃ into Na_0.5Bi_0.5TiO₃(NBT) (x NN-(1-x) NBT, where x= 0.17, 0.19, 0.21, 0.23, and 0.25). To overcome limitations of NBT, additional constituents with antiferroelectric properties were introduced to create binary solid solutions with NBT to yield NN-NBT ceramics with antiferroelectric properties for optimized energy storage applications. As-obtained NN-NBT ceramics revealed multiphase structures with rhombic (R3c) and tetrahedral (P4bm) phases. Coexisting strongly and weakly coupled polar nanoregions (PNRs) resulted in relatively high polarization (P_max) and reduced polarization of reflection (P_r). The optimized 0.21NN-0.79NBT ceramic exhibited recoverable energy storage density of ≈2.84 J·cm⁻³ at 180 kv·cm⁻¹ with energy storage efficiency of 78%. Structural characterization indicated the existence of intermediate phases modulation phases with coexisting antiferroelectric phase and relaxation ferroelectric phase. Overall, proposed NBT-based non-ergodic relaxation ferroelectric ceramics look promising for effectively improving energy storage performance, providing new prospects for the development of advanced pulse capacitors.