Achieved high energy density and excellent thermal stability in (1-x)(Bi_(0.5)Na_(0.5))_(0.94)Ba_(0.06)TiO_3-xBi (Mg_(0.5)Ti_(0.5)O_3 relaxor ferroelectric thin films

摘要

In this work, lead-free (1-x)(Bi_(0.5)Na_(0.5))_(0.94)Ba_(0.06)TiO_3-xBi(Mg-(0.5)Ti_(0.5))O_3 (abbreviated as BNBT-xBMT, x = 0.3, 0.4,0.5 and 0.6) thin films were prepared on Pt/Ti/SiO_2/Si substrates using sol-gel method. The microstructures, dielectric, and energy storage properties were investigated. The results showed that the addidon 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 fikns was also reduced by the doping of a moderate amount of BMT. A high recoverable energy density of 34.36 J/cm~3 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 ×10~5 cycles. These results suggest that BNBT-0.5BMT thin film may be a promising material for lead-free dielectric energy storage applications.