Excellent Energy-Storage Performance of (0.85 - x )NaNbO 3 - x NaSbO 3 -0.15(Na 0.5 La 0.5 )TiO 3 Antiferroelectric Ceramics through B-Site Sb 5+ Driven Phase Transition.

NaNbO 3 -based relaxor antiferroelectric (AFE) ceramics are receiving more and more attention for high power pulse applications. A commonly used design strategy is to add complex perovskites with lower tolerance factors. Herein, a new lead-free AFE system of (0.85 - x )NaNbO 3 - x NaSbO 3 -0.15(Na 0.5 La 0.5 )TiO 3 was specially designed considering the substitution of Sb 5+ for Nb 5+ reduces the polarizability of B-site ions but increases the tolerance factor. The formation of nanodomains with stable AFE orthorhombic R phase symmetry contributes to a slim and double-like polarization-field hysteresis loop, while the increased resistivity and activation energy as a result of sintering aids lead to an enhanced breakdown strength. Therefore, an excellent energy density W rec ≈ 6.05 J/cm 3 , a high energy efficiency η ≈ 80.5%, and good charge-discharge performances (power density P D ≈ 155 MW/cm 3 and discharging rate t 0.9 ≈ 44.6 ns) were achieved in MnO 2 -doped x = 0.03 ceramics. The experimental results demonstrate that the B-site Sb 5+ driven orthorhombic P-R phase transition and increased local structure disorder should provide a new strategy to design high-performance NaNbO 3 -based relaxor AFE capacitors.