Significantly improved energy storage performance of NBT-BT based ceramics through domain control and preparation optimization

Na_0.5Bi_0.5TiO₃-BaTiO₃ based lead-free ceramic possesses ideal ferroelectric properties, and it is hence expected to be used as a new generation of pulse power capacitors. However, NBT-BT based ceramics usually belong to macro domains, leading to a large residual polarization and coercive field, which making it difficult to be widely used as energy storage materials. Therefore, a strategy combining with both domain control and processing optimization via viscous polymer process was designed to enhance the energy storage properties. In this study, SBT and lanthanide elements were introduced into NBT-BT to transform the macro domain into micro domain, which effectively reduced the residual polarization and coercive field. Meanwhile, the viscous polymer process effectively increased the electric breakdown strength of ceramics. The resulting ceramics obtained high E and W_rec at room temperature, reaching 270 kV and 4.87 J/cm³, respectively. This strategy is expected to benefit other ceramics for pulse power supply.