Novel BiFeO ₃ –BaTiO ₃ –Ba(Mg 1/3 Nb 2/3 )O ₃ Lead‐Free Relaxor Ferroelectric Ceramics for Energy‐Storage Capacitors

A novel lead‐free relaxor ferroelectric ceramic of (0.67− x )BiFeO 3 –0.33BaTiO 3 – x B a(Mg 1/3 Nb 2/3 )O 3 [(0.67− x ) BF –0.33 BT – x BMN , x = 0–0.1] was prepared by a solid‐state reaction method. A relatively high maximum polarization P max of 38 μC/cm 2 and a low remanent polarization P r of 5.7 μC/cm 2 were attained under 12.5 kV/mm in the x = 0.06 sample, leading to an excellent energy‐storage density of W ~1.56 J/cm 3 and a moderate energy‐storage efficiency of η ~75%. Moreover, a good temperature stability of the energy storage was obtained in the x = 0.06 sample from 25°C to 190°C. The achievement of these characteristics was basically attributed to an electric field induced reversible ergodic to ferroelectric phase transition owing to similar free energies near a critical freezing temperature. The results indicate that the (0.67− x ) BF –0.33 BT – x BMN lead‐free realxor ferroelectric ceramic could be a promising dielectric material for energy‐storage capacitors.