Enhanced the energy storage performance in AgNbO3‑based antiferroelectric ceramics via manipulation of oxygen vacancy

The applications of silver niobate (AgNbO3)-based antiferroelectric (AFE) ceramics for potential energy storage are limited by the introduction of oxygen vacancies (OVs). The inevitable OVs narrow the band gap and promote grain growth, resulting in poor breakdown strength and low recoverable energy density (Wrec). Here, we report a significant energy density performance of (Ag1–2xSrx)(Nb0.78Ta0.22)O3 AFE ceramics designed by restraining OVs. Electron paramagnetic resonance (EPR) and UVvis absorption spectra experiments demonstrate that the OV content gradually decreases and the band gap increases with increasing Sr content. Donor doping of Sr leads to the generation of silver ion vacancies, thus, the OV concentration decreases to maintain the electrical neutrality of the system. As a result, a high Wrec of ∼5.6 J/cm3 together with an energy efficiency of 70.1% at 300 kV/cm is achieved in the (Ag0.92Sr0.04)(Nb0.78Ta0.22)O3 ceramic. This work offers a novel strategy for improving the energy storage properties of AgNbO3-based AFE ceramics.