Boosting energy storage performance of BiFeO3-based multilayer capacitors via enhancing ionic bonding and relaxor behavior

Abstract

Environmentally friendly BiFeO₃ 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)BiFeO₃-0.3BaTiO₃-xNaTaO₃ + 0.3 wt% MnO₂ (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 BiFeO₃, which is via enhancing ionic bonding and relaxor behavior to achieve high BDS, low P_r and large P_max, simultaneously.