High energy storage property and breakdown strength of Bi0.5(Na0.82K0.18)0.5TiO3 ceramics modified by (Al0.5Nb0.5)4+ complex-ion.

The influence of B-site (Al 0.5 Nb 0.5 ) 4+ complex-ion substitution on the phase transition, microstructure, dielectric, ferroelectric, and energy-storage properties of Bi 0.5 (Na 0.82 K 0.18 ) 0.5 Ti 1– x (Al 0.5 Nb 0.5 ) x O 3 (BNKT- x AN) ceramics were systematically investigated. BNKT- x AN ceramics showed single-phase perovskite structure without an obvious phase transition after adding AN. Compact and uniform microstructure with almost the same grain morphology and size was obtained. The AN doping produced slimmer P - E loops and thus improved energy storage property. Meanwhile, the energy storage density increases drastically, and a maximum value of 1.41 J/cm 3 at 105 kV/cm was achieved in BNKT-0.08AN through increasing greatly its breakdown strength with more AN content. The temperature dependence of dielectric constant and dielectric loss of BNKT- x AN ceramics illustrated the obvious relaxor phase transition characteristics. Low ionic conductivity and electronic conductivity indicated the BNKT- x AN ceramics have excellent dielectric properties. These results indicated that the BNKT-AN system may be a promising lead-free material for high energy storage density capacitor. [ABSTRACT FROM AUTHOR]