Structure, electrical properties and energy storage performance of BNKT-BMN ceramics

In this work, Bi(Mg 2/3 Nb 1/3 )O 3 (BMN) was introduced to improve the electrical properties and energy storage performance of Bi 0.5 (Na 0.82 K 0.18 ) 0.5 TiO 3 (BNKT) ceramics, and the lead-free ceramics BNKT- x BMN ( x = 0.02, 0.04, 0.06, 0.08, 0.10, 0.12, 0.14, 0.16) were synthesized via a traditional sintering process. The relaxation behavior and thermal stability of the materials were enhanced as well as the temperature corresponding to the maximum permittivity decreased monotonously from about 300 °C at x = 0, to 250 °C at x = 0.16 with the increasing of BMN content. Besides, a slim P - E loop with a large ∆ P was obtained after doped BMN. Eventually, at a BMN doping level of 0.08, a BNKT-0.08BMN ceramic obtained high energy storage density of 2.20 J/cm 3 as well as an acceptable efficiency of 55.7% under a low electric field of 110 kV/cm. Furthermore, a good temperature/frequency stability was achieved in BNKT-0.08BMN ceramic, as well as glorious fatigue behavior of energy storage properties. This work not only clarifies the internal relationship between the structure and properties of BNKT-BMN, but also provides useful insights for the optimization of electrical properties and energy storage behavior of lead-free energy storage bulk materials.