Enhanced energy storage performances under moderate electric field in aliovalent A/B-site co-doped AgNbO3

Energy storage properties of Nd3+ and Hf4+ A/B-site co-doped AgNbO3 (Ag1-2xNdxNb1-xHfxO3, x = 0.005–0.02) ceramics were investigated. The introduction of Nd3+ and Hf4+ stabilizes the antiferroelectric phase and enhances the energy storage density. Besides, aliovalent doping of Nd3+ and Hf4+ increases the relaxor characteristic, leading to low energy storage loss in the polarization and high energy storage efficiency. Above the antipolar dipole freezing temperature (Tf), temperature-stable polarization is obtained, leading to a good temperature stability of energy storage properties. Ag0.97Nd0.015Nb0.985Hf0.015O3 exhibits excellent energy storage performances, with a recoverable energy storage density of 3.94 J/cm3 and energy storage efficiency of 64.0% under a moderate electric field of 235 kV/cm. The energy storage density increases with the temperature, and the energy storage efficiency maintains good temperature stability, with a variance of 11% in the range of 25 °C to 175 °C under an applied electric field of 200 kV/cm.