Realizing Superior Energy Storage Performance and Ultrafast Discharge Rate in NaNbO₃-Based Ceramics by Multiscale...

Dielectric capacitors exhibit great promise for use in advanced energy storage devices. Nevertheless, realizing a large energy storage density (W_rec) and high efficiency (η) remains an arduous challenge. In this work, a multiscale manipulation strategy was employed by integrating polar-nanoregions (PNRs) regulation at the nanoscale and grain-structure regulation at the microscale to enhance energy storage performance of NaNbO₃-based ceramics. The incorporation of (Bi_0.5Na_0.5)_0.7Sr_0.3TiO₃ (BNST) into (Na_0.94La_0.06)(Nb_0.88Zr_0.12)O₃ (NLNZ) ceramics induces a high amount of PNRs at the nanoscale, thereby giving rise to a high η and an ultrafast discharge rate. In addition, at the microscale, the decreased grain size and dense structure enhance the resistivity as well as the activation energy of the ceramics, thus leading to a large breakdown electric field (E_b) and consequently an enhanced W_rec. At last, the optimal energy storage performance (W_rec ∼ 9.3 J/cm³, η ∼ 82.4% at E_b ∼ 920 kV/cm) was realized in the 0.80NLNZ-0.20BNST ceramic through the multiscale manipulation. Furthermore, the 0.80NLNZ-0.20BNST ceramic also demonstrates excellent stabilities under varying frequency (1-500 Hz), temperature (20-160 °C), and cycling (1-10⁶ cycles) as well as outstanding charge/discharge performances (power density P_D ∼ 407 MW/cm³, current density C_D ∼ 1659 A/cm², and discharge rate t_0.9 ∼ 13 ns). These results suggest that the 0.80NLNT-0.20BNST ceramic exhibits a significant energy storage application potential.