Enhanced energy storage performance in NaNbO3-modified (Bi0.5Na0.5)0.94Ba0.06TiO3-based ceramics through composite doping strategy

Due to their high power density, rapid charging and discharging rate, and environmental friendliness, lead-free dielectric capacitors are receiving extensive attention in energy storage devices. Whereas, their inherent low recoverable energy density ( W rec ) remains a bottleneck that restricts their practical application. It is of great significance to exploit lead-free dielectric ceramics with high energy storage capacity and good reliability. In this work, NaNbO 3 (NN)-modified [(Bi 0.5 Na 0.5 ) 0.94 Ba 0.06 ] 0.6 (Bi 0.2 Sr 0.7 ) 0.4 TiO 3 (BNBT-SBT) ceramics were developed to obtain excellent energy storage characteristics. The results revealed that NN doping leads to the refinement of grain, the enhancement of relaxation behavior, the increase of resistivity, and the expansion of band gap, observably improving the breakdown strength ( E b ). Notably, under a great E b of 697 kV/cm, the BNBT-SBT-0.07NN ceramic exhibits superior energy storage characteristics with W rec of 7.46 J/cm 3 and efficiency ( η ) of 82.3 %. Furthermore, this system displays good thermal stability, frequency stability, and charge-discharge features. These findings suggest that NN modification can effectively tailor the energy storage performance of BNBT-based ceramics, and the as-prepared BNBT-SBT-0.07NN system has the potential to be applied in pulsed power systems.