Boosting energy storage performance of BiFeO ₃-based multilayer capacitors via enhancing ionic bonding and relaxor behavior

Abstract

F-BT- xNT MLCCs were designed and expected to achieve high energy-storage density because of ultrahigh P _s value of BiFeO ₃ system. With enhancement of ionic bonding and dielectric relaxation, excellen U _rec = 9.1 J cm ⁻³ and η > 80% were achieved at x = 0.12.

Abstract

Environmentally friendly BiFeO ₃ capacitors have great potential for applications in pulsed-discharge and power conditioning electronic systems because of their excellent intensity of spontaneous polarization ( P _s). Herein, (0.7− x)BiFeO ₃-0.3BaTiO ₃- xNaTaO ₃ + 0.3 wt% MnO ₂ (abbreviated as BF-BT- xNT) multilayer ceramic capacitors (MLCCs) were designed and prepared to improve the energy storage performance via enhancing ion bonding and dielectric relaxation. The BDS of BF-BT- xNT MLCCs from 500 kV cm ⁻¹ at x = 0.05 increases greatly to 800 kV cm ⁻¹ at x = 0.15 due to the increase of the band gap and resistance, and the decrease of dielectric permittivity. An excellent energy storage density U _rec = 9.1 J cm ⁻³ and efficiency η > 80% were obtained since ultrahigh BDS (780 kV cm ⁻¹) and low P _r value (2.1 μC cm ⁻² at measured electric field 780 kV cm ⁻¹) were achieved simultaneously in BF-BT- xNT multilayer capacitors at x = 0.12. This work provides a strategy for improving energy storage properties of BiFeO ₃, which is via enhancing ionic bonding and relaxor behavior to achieve high BDS, low P _r and large P _max, simultaneously.