Lead-free (Na_1–1.5xBi_xLa_0.5x)(Nb_1-xMg_x)O₃ ceramics with high energy storage performance via ionic co-doping induced local antiferroelectric phases coexistence

Antiferroelectric materials have garnered considerable interest for pulsed power applications because of their reversible antiferroelectric-ferroelectric (AFE-FE) phase transition under an electric field. However, pure NaNbO₃ exhibits ferroelectric phase characteristics at room temperature under an electric field, resulting in low energy storage performance. We prepared lead-free (Na_1–1.5xBi_xLa_0.5x)(Nb_1-xMg_x)O₃ ceramics via inducing local antiferroelectric phases coexistence by ion co-doping. The P-R phase transition temperature was shifted below room temperature, which promotes the formation of polar nanoregions and achieves a favorable ΔP value (52 μC·cm⁻²) when x = 0.06. Consequently, the sample with x = 0.06 achieved a high energy storage density (8.24 J·cm⁻³), energy storage efficiency (93.7 %), and energy storage potential (23.54 J·cm⁻²·MV⁻¹) at 350 kV·cm⁻¹, while exhibiting excellent frequency (1–1000 Hz) and temperature (25–150 °C) stability. This work presents a practical approach to develop capacitors with high energy storage performance for other systems under the same electric field range.