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

Wang, Dawei, Fan, Zhongming, Zhou, Di, Khesro, Amir, Murakami, Shunsuke, Feteira, Antonio, Zhao, Quanliang, Tan, Xiaoli, Reaney, Ian M.
Journal of materials chemistry 2018 v.6 no.9 pp. 4133-4144
bismuth, ceramics, electrical equipment, energy, energy density, ferrimagnetic materials
Lead-free ceramics with high recoverable energy density (Wᵣₑc) 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(Bi₁₋ₓNdₓ)FeO₃-0.25BaTiO₃ (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 Wᵣₑc ∼ 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 (Pₘₐₓ ∼ 40 μC cm⁻²). The multilayers of this composition possessed both a high Wᵣₑc 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 Wᵣₑc are therefore considered promising candidates for lead-free energy storage applications.