Antiferroelectric phase regulation for constructing BNT-based relaxor ferroelectric ceramics: A breakthrough in ultra-high energy storage performance under moderate electric fields

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.