Achieved High Energy Density and Excellent Thermal Stability in (1-x)(Bi0.5Na0.5)0.94Ba0.06TiO3-xBi(Mg0.5Ti0.5)O3 Relaxor Ferroelectric Thin Films

Abstract In this work, lead-free (1-x)(Bi0.5Na0.5)0.94Ba0.06TiO3-xBi(Mg0.5Ti0.5)O3 (abbreviated as BNBT-xBMT, x = 0.3, 0.4, 0.5 and 0.6) thin films were prepared on Pt/Ti/SiO2/Si substrates using sol-gel method. The microstructures, dielectric and energy storage properties were investigated. The results showed that the addition of BMT disrupted the long-range ferroelectric order and enhanced the relaxor behavior of BNBT-xBMT thin films. In addition, the leakage current density of thin films was also reduced by the doping of moderate amount of BMT. A high recoverable energy density of 34.36 J/cm3 with an efficiency of 56.63% was achieved in the BNBT-0.5BMT thin film under the electric field of 2149 kV/cm. Furthermore, BNBT-0.5BMT thin film exhibited superior stability in the temperature range of 30°C − 145°C and frequency range of 500 Hz − 5 kHz, as well as long-term fatigue durability after 1 × 105 cycles. These results suggest that BNBT-0.5BMT thin film may be a promising material for lead-free dielectric energy storage applications.