AgNbO3-based antiferroelectric ceramics with superior energy storage performance via Gd/Ta substitution at A/B sites

Dielectric materials have attracted considerable attention owing to their excellent power densities and fast charge/discharge characteristics. AgNbO3, as a typical antiferroelectric (AFE) material, is regarded as a promising dielectric material owing to its large polarization value and environmentally friendly nature. However, the low energy density of this system limits its further application. In this study, the slim P-E loops are implemented by Gd/Ta substitution at A/B sites, which provide a superior energy storage performance with a Wrec of 6.99 J/cm3 under 400 kV/cm. This improvement in energy storage property can be attributed to three factors: firstly, a significant improvement in the AFE stability is obtained by reducing the tolerance factor t and the B-site polarizability; secondly, this strategy leads to a reduction in the grain size of the material, optimizing the breakdown electric field Eb of AN-based ceramics; lastly, A/B-site codoping induces structural distortion of the material, constructs an internal chemical pressure, and suppresses its oxide octahedral tilting. Furthermore, the Gd/Ta co-doped ceramics exhibit an excellent practical charging/discharging efficiency (＜10 μs). This work demonstrates that the electrical properties of AN-based ceramics have been optimized by Gd/Ta codoping, making them good candidates for pulsed power systems.