Excellent energy storage performance in La and Ta co-doped AgNbO3 antiferroelectric ceramics

Lead-free dielectric materials with high breakdown electric field strength and energy density are required for pulsed power devices with high level of integration. This work describes: (Ag0.94La0.02)(Nb1-xTax)O3 lead-free antiferroelectric ceramics, which were prepared by rolling process. Following composition engineering, an outstanding energy density of 6.9 J cm-3 at electric field of 490 kV cm-1 was achieved, coupled with remarkable frequency stability (<1% over 1-100 Hz under E = 420 kV cm-1) for (Ag0.94La0.02)(Nb0.80Ta0.20)O3 ceramics. Moreover, it also shows excellent charge-discharge properties (discharge density = 1429 A cm-2, power density = 144 MW cm-3). The addition of La3+ and Ta5+ induced a disordered local structure, which gradually decreased the phase transition temperature of M2-M3 to room temperature, reflecting the enhanced antiferroelectricity. All advantageous properties observed for the La and Ta co-doped AgNbO3 ceramics highlight their significant potential for energy storage applications.