Grain size tailoring and enhanced energy storage properties of two-step sintered Nd3+-doped AgNbO3

AgNbO3 as a lead-free antiferroelectric material, has received widespread attention in recent years due to its promising application in the aspects of energy storage devices. However, the high remnant polarization and low breakdown strength limits its energy storage properties. In this work, Nd3+-doped AgNbO3 (Ag1−3xNdxNbO3, x=0−0.015) ceramics were prepared and a two-step sintering method was employed. The introduction of Nd3+ leads to the enhanced stability of the antiferroelectric phase, refined grain size and increased resistivity. Furthermore, by adjusting the pre-heating temperature in the two-step sintering, the homogeneity of microstructure is improved and the resistance of pre-heated samples increases by one order of magnitude compared with normally sintered samples, leading to the enhanced breakdown strength. Ag0.97Nd0.01NbO3 pre-heated at 1100 °C for 2 h exhibits promising energy storage properties, with a recoverable energy storage density of 3.2 J/cm3 and energy efficiency of 52 % under an applied electric field of 210 kV/cm.