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

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)BiFeO3-0.3BaTiO(3)-xNaTaO(3) + 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 eta > 80% were obtained since ultrahigh BDS (780 kV cm(-1)) and low P-r value (2.1 mu C 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.