Promoting Energy Storage Performance of Sr0.7Ba0.3Nb2O6 Tetragonal Tungsten Bronze Ceramic by a Two-Step Sintering Technique

Dielectric ceramic capacitors have attracted immense interest because of their remarkable power density and excellent charging–discharging performance. Tetragonal tungsten bronze (TTB)-based ferroelectrics are the second large category of ferroelectric materials. However, they have not received enough appreciation in the dielectric capacitor field because of their poor energy storage properties. In this study, a two-step sintering technique was employed to prepare TTB relaxor ferroelectric ceramic Sr0.7Ba0.3Nb2O6 (SBN70), aiming to promote its energy storage performance. Remarkable recoverable energy storage density (Wrec ∼ 3.2 J/cm3) and excellent efficiency (η ∼ 90%) were realized simultaneously, which profited from the reduction of the average grain size and the enhancement of the breakdown strength. Moreover, the ceramic also exhibited an ultrashort discharge time (<65 ns), great discharge current density (789.8 A/cm2), and large power density (79 MW/cm3). The obtained results indicate the immense potential of TTB structure relaxor ferroelectric ceramics for energy storage applications.