Comprehensive energy-storage performance enhancement in relaxor anti-ferroelectrics via strengthening local polarization

Lead-free dielectric capacitors with excellent energy-storage performance have gained much attention for their remarkable potential applications in pulsed power electronic systems and devices. However, the large recoverable energy-storage density Wrec is usually accompanied with low efficiency η, hindering their practical applications. Such performance deterioration occurs because the large polarization is generally linked with strong reversal hysteresis, making the synergetic optimization of energy-storage density and efficiency a great challenge. Here we develop a strategy of constructing strengthened local polarization in the lead-free relaxor anti-ferroelectric ceramics 0.9NaNbO3-0.1Bi(Ni2/3Nb1/3)O3 by carefully manipulating the microstructures, the ultrahigh Wrec ∼ 11.2 J/cm3 and large η ∼ 90.5 % have been simultaneously achieved. Moreover, superior charge/discharge performances (power density PD ∼ 548 WM/cm3, discharge speed t0.9 ∼ 27 ns) and outstanding temperature (up to 160 °C) and cycling (up to 106) stabilities are also ensured. The excellent overall properties are mainly attributed to the stabilized antiferroelectric phase, the strong relaxation characteristic, as well as the enhanced local polarization in the polar nano-regions (PNRs) caused by the introduction of Bi(Ni2/3Nb1/3)O3. This work not only provides a lead-free system with remarkable energy-storage performance that demonstrates great potential in the application field of high-power pulse electronic devices, but also proposes a convenient and efficient strategy to design new dielectric materials with excellent energy-storage performance.