Improving the energy storage performance under moderate electric fields in BiFeO3-based ceramics through a co-doping strategy

The development of ceramic capacitors with superior energy storage capabilities (>5 J/cm 3 ) under moderate electric fields (300–500 kV/cm) is essential for their practical integration into advanced electronic devices. Here, (1- x )(0.67BiFeO 3 -0.33BaTiO 3 )- x Na(Ta 0.5 Nb 0.5 )O 3 ( x  = 0–0.25) ceramics are successfully synthesized, demonstrating exceptional energy storage performance. Specifically, the appropriate introduction of the Na(Ta 0.5 Nb 0.5 )O 3 can disrupt the long-range ordered structure in the ferroelectric samples and suppress the octahedral distortion, promoting the formation of polar nanoregions and reducing the remanent polarization. Meanwhile, a large bandgap and conductive activation energy endow it with a high breakdown strength. As a result, a high recoverable energy storage density of 6.44 J/cm 3 and a high energy storage efficiency of 87 % are achieved in the as-synthesized 0.8BFBT-0.2NTN samples under 440 kV/cm, with excellent frequency stability, temperature stability, and fatigue stability. This work presents a viable strategy for improving the energy storage properties of BiFeO 3 -based ceramics under moderate electric fields, offering significant potential for next-generation energy storage applications.