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.
Although high-power-density lead-free ceramic-based dielectric capacitors are considered promising candidates for energy storage applications, achieving a high recoverable energy density ( W rec > 5 J cm −3 ) typically requires the application of an external electric field ( E > 400 kV cm −1 ), which poses significant risks to the electrical insulation system. Therefore, the development of lead-free dielectric ceramics that exhibit high energy storage performance under moderate electric fields (300 < E < 500 kV cm −1 ) has become a critical research focus. In this study, a ferroelectric - antiferroelectric binary solid solution was constructed by incorporating the antiferroelectric material NaNbO 3 into Bi 0.2 Na 0.4 Ba 0.2 La 0.2 TiO 3 ceramics. Experimental results demonstrate that the incorporation of the antiferroelectric phase effectively reduces grain size, widens the band gap, and significantly enhances the relaxation behavior, thereby enabling a high maximum polarization ( P max ) and a low remnant polarization ( P r ) under moderate electric fields. Consequently, the 0.95Bi 0.2 Na 0.4 Ba 0.2 La 0.2 TiO 3 -0.05NaNbO 3 ceramic achieved an ultra-high W rec of 6.42 J cm −3 and an excellent energy storage efficiency of 89.4 % under a moderate electric field of 400 kV cm −1 , along with outstanding thermal and frequency stability. This work presents a promising strategy for developing dielectric materials with superior energy storage performance under moderate electric fields, aligning well with the requirements of advanced energy storage technologies.
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