Bismuth ferrite-based lead-free ceramics and multilayers with high recoverable energy density

Lead-free ceramics with high recoverable energy density (W rec ) and energy storage efficiency (η) are attractive for advanced pulsed power capacitors to enable greater miniaturization and integration. In this work, dense bismuth ferrite (BF)-based, lead-free 0.75(Bi 1-x Nd x )FeO 3 -0.25BaTiO 3 (BNxF-BT) ceramics and multilayers were fabricated. A transition from a mixed pseudocubic and R3c to a purely pseudocubic structure was observed as x increased with the optimum properties obtained for mixed compositions. The highest energy densities, W ∼ 4.1 J cm -3 and W rec ∼ 1.82 J cm -3 , were achieved for BN15F-BT, due to the enhanced breakdown field strength (BDS ∼ 180 kV cm -1 ) and large maximum polarization (P max ∼ 40 μC cm -2 ). The multilayers of this composition possessed both a high W rec of 6.74 J cm -3 and η of 77% and were stable up to 125 °C. Nd doped BF-based ceramics with enhanced BDS and large W rec are therefore considered promising candidates for lead-free energy storage applications.