Improved energy storage properties achieved in NaNbO₃-based relaxor antiferroelectric ceramics via anti-parallel polar nanoregion design

With the increase in environment protection requirements and the development of pulse-power technology, environmentally friendly antiferroelectric materials with superior energy storage performance have received increasing attention. The present work proposes a combinatorial optimization technique to optimize the energy storage capabilities of NaNbO₃-based ceramics, that is, the AFE P phase can be stabilized and anti-parallel polar nanoregions (APNRs) are proposed to reduce the electric field-induced remnant polarization response (decrease P_r) by introducing Bi(Zn_0.5Hf_0.5)O₃ into the NaNbO₃ ceramic, then further use of rolling to increase the breakdown strength (enhance E_b). Consequently, a large W_rec of 5.82 J cm⁻³ and an outstanding η of 86.7% at 531 kV cm⁻¹ are obtained by a repeated rolling process, together with excellent frequency (1-200 Hz) and cycling (1-10⁶) stability. Here, the results show that the combinatorial optimization technique is effective in developing the energy storage performance of lead-free ceramics.