Realizing high energy density and efficiency simultaneously in (Bi0.5Na0.5)0.7Sr0.3TiO 3-based ceramics via introducing linear dielectric CaTiO3

摘要

Modern electronics and electrical power systems require a high energy storage density (W-rec) and a large efficiency (eta) to deliver high performances. Although dielectric capacitors have been extensively explored owing to their numerous advantages, it is still a great challenge to develop dielectric materials with excellent comprehensive energy storage performances. Herein, we demonstrate that an ultrahigh W-rec of 7.0 J cm(-3) and a large eta of 90.9% are obtained simultaneously in 0.60(Bi0.5Na0.5)(0.7)Sr0.3TiO3-0.40CaTiO(3) ceramics by the synergistic contribution of delayed low-field polarization saturation and improved breakdown strength (E-b). The composition-driven fine domain size delays low-field polarization saturation and enhances eta, which are confirmed by experimental characterization [high-resolution transmission electron microscopy (HR-TEM) and piezoresponse force microscopy (PFM)] and analysis using multiple models (V-F model, macroscopic and phenomenological model, and conceptual model based on the Landau-Devonshire theory). Phase-field simulations confirm that the fine grain size contributes to the enhancements of E-b. This contribution provides a feasible paradigm for designing dielectric materials exhibiting high energy storage performances and reveals fundamental insights into the origin of delayed polarization saturation and high E-b.

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