Effects of sintering method on the structural, dielectric and energy storage properties of AgNbO3 lead-free antiferroelectric ceramics

In this work, we systematically investigated the effects of single-step and two-step sintering methods on the structural, dielectric and energy storage properties of pure AgNbO3 lead-free antiferroelectric ceramics. Compared with the single-step sintered ceramic, the ceramic prepared by two-step sintering method has smaller grain size, dense and homogeneous microstructure. In addition, the results of dielectric temperature spectra reveal that the two-step sintering method hardly changes the phase transition temperature of AgNbO3 ceramics but greatly decreases the dielectric loss value. Most importantly, the ceramic prepared by the two-step sintering method displays high breakdown electric field strength (22 kV/mm), larger recoverable energy storage density-Wrec (2.59 J/cm3) and higher energy storage efficiency-η (45%) as well as excellent temperature stability than those of the ceramic by single-step sintering method. Furthermore, it also exhibited high power density (PD = 25.7 MW/cm3) and extremely fast charge–discharge speed (25 ns). Our results provide a simple and novel way to design high-performance AgNbO3-based energy storage lead-free ceramics.