Excellent low-field energy storage properties and high density achieved in Bi0.48Na0.48Ba0.04TiO3-based oxide ceramics via interposing (Na0.97Bi0.01)+/Ta5+ at A/B sites

Lead-free dielectric ceramics are one of the most essential candidates for reforming pulsed power capacitors; nevertheless, formidable hurdles are posed by their high hysteresis and low energy storage properties. Dielectric ceramic capacitors with ultra-high energy storage performance usually need to be realized under the conditions of high electric field. Its application in miniaturized integrated electronic devices is severely limited. In this work, A-site deficiency was designed in Na0.97Bi0.01TaO3-modified Bi0.48Na0.48Ba0.04TiO3 lead-free relaxor ferroelectric ceramics to increase oxygen vacancy content, achieve local disorder and construct local multi-phase coexistence, which causes low hysteresis with excellent high energy density at low electric fields (LEFs). Results indicated that the introduction of A-site deficiency improved the concentration of oxygen vacancies while reconstructing the local structure disorder. Benefiting from the synergistic effect of both, a high energy recoverable density of similar to 7.98 J cm-3 and efficiency eta of similar to 83.7% was determined in 0.84Bi0.48Na0.48Ba0.04TiO3-0.16Na0.97Bi0.01TaO3-modified ceramics under 330 kV cm-1. Furthermore, the modified ceramics had an acceptable frequency stability (0.5-130 Hz) and temperature stability (RT - 180 degrees C) with exact discharge density. These findings can lead to the development of an innovative strategy for fabricating energy-storage ceramics under low electric field conditions.