Enhanced energy-storage properties of 0.89Bi_0.5Na _0.5TiO₃-0.06BaTiO₃-0.05K_0.5Na _0.5NbO₃ lead-free anti-ferroelectric ceramics by two-step sintering method

This work compared the effects of different sintering methods on the microstructure and anti-ferroelectric properties of lead-free 0.89Bi _0.5Na_0.5TiO₃-0.06BaTiO₃-0.05K _0.5Na_0.5NbO₃ ternary system ceramics. The ceramics by two-step sintering method had smaller grain size and more uniform microstructure than those of the ceramics by single-step sintering method. The mechanism of grain growth in different sintering methods is discussed. The ceramics by two-step sintering method exhibited better anti-ferroelectricties than those of the ceramics by single-step sintering method. The polarization hysteresis (P-E) loop showed optimum electrical performances with a low remanent polarization (P_r=5.4 μC/cm²) and a coercive field (E_c=8.2 kV/cm), and the energy density (W) reached 0.90 J/cm ³ at 10 Hz. The storage capacity is three times that of the single-step sintering ceramics.