Enhanced breakdown strength and energy storage density in a new BiFeO3-based ternary lead-free relaxor ferroelectric ceramic

Abstract A new ternary lead-free relaxor ferroelectric ceramic of (0.67-x)BiFeO 3 -0.33(Ba 0.8 Sr 0.2 )TiO 3 -xLa(Mg 2/3 Nb 1/3 )O 3 +y wt.% MnO 2 +z wt.% BaCu(B 2 O 5 ) (BF-BST-xLMN+y wt.% MnO 2 +z wt.% BCB) was prepared by a solid-state reaction method. The substitution of LMN for BF was believed to induce a typical dielectric relaxation behavior owing to the increased random fields. After co-doping MnO 2 and BCB, a significant decrease in the conductivity and grain size was simultaneously realized, resulting in obviously enhanced dielectric breakdown strength and energy-storage performances at room temperature. A high recoverable energy storage density W ˜3.38 J/cm 3 and an acceptable energy storage efficiency η˜59% were achieved in the composition with x = 0.06, y = 0.1 and z = 2 under a measuring electric field of 23 kV/mm. In addition, the energy-storage performance is quite stable against both frequency (0.1 Hz–100 Hz) and temperature (30–170 °C), suggesting that BF-BST-xLMN+y wt.% MnO 2 +z wt.% BCB lead-free relaxor ferroelectric ceramics might be a promising dielectric material for high-power pulsed capacitors.