Antiferroelectric stability and energy storage properties of Co-doped AgNbO3 ceramics

AgNbO3 ceramics have attracted progressively more attention to high power energy storage in dielectric capacitors because of complicated in a series of phase transitions. In this work, Ag1-3xBixNb1-3/5xScxO3 (x ​= ​0, 0.005, 0.01, 0.02) ceramics were synthesized via a solid state reaction method in flowing oxygen. The microstructure, dielectric and energy storage properties of as-prepared samples were systematic characterized to evaluate the potential as high energy storage capacitors. A high recoverable energy storage density (3.65 ​J/cm3) and high efficiency (84.31%) were simultaneously obtained in a modified AgNbO3-based ceramic at 21.5 ​MV/m. The energy storage performance is improved by the ions doping that effectively interrupt the dipoles arrangement structure and stabilize the disordered antiferroelectric phase in the long-range order. Co-doping of Bi3+ on the A-site and Sc3+ on the B-site in AgNbO3 is an effective method to enhance the electric field intensity of field-induced phase transitions from antiferroelectric (AFE) to ferroelectric (FE) phases. The M1-M2 phase transition shifted to a lower temperature with an increase in the Bi/Sc amounts, which suppressed the ferroelectricity and obtained pinched-hysteresis loops in modified AgNbO3 ceramics. These results indicate that Bi/Sc co-doped AgNbO3 ceramics are highly efficient lead-free antiferroelectric materials for prospective application in high-performance energy storage capacitors.