Enhanced energy-storage performance in BNT-LST-based ceramics via polarization optimization and breakdown strength regulation

Dielectric storage ceramics are widely used in electronic products due to their speed charge-discharge rate. However, the low recoverable energy density, which is attributing to the high remanent polarization and low breakdown electric field, results in an inferior efficiency, which hinders their applications. Here, superior energy storage properties were achieved in the pseudo-cubic 0.5(Bi0.5Na0.5)TiO3-0.5(La0.1Sr0.8)TiO3-delta (BNT-0.5LST) ceramics at 323 kV/cm, and the recoverable energy density, energy efficiency, and breakdown strength in BNT0.5LST ceramics were severally enhanced 10 times, 5.9 times and 1.3 times than those of BNT-0.1LST ceramics. Slim P-E loops and high polarization (28.13 mu C/cm2) originated from the presence of polar nano-regions (PNRs), and the PNRs with weakly couple with each other decreased the remanent polarization. Large breakdown strength attributed to the broad band gap (3.302 eV) and refined grain (1.59 mu m). Transmission electron microscopy proved the presence of PNRs in the pseudo-cubic matrix phase. The results have provided a novel route for fabricating the storage ceramics with the outstanding energy storage properties.