High energy-storage density of lead-free BiFeO 3 doped Na 0.5 Bi 0.5 TiO 3 -BaTiO 3 thin film capacitor with good temperature stability

In this work, the lead-free and BiFeO3 doping Na0.5Bi0.5TiO3-BaTiO3 thin films [(0.94-x)Na0.5Bi0.5TiO3-0.06BaTiO3-xBiFeO3 (NBT-6BT-xBFO), x = 0.00, 0.01, 0.03, 0.05 and 0.07] were deposited on Pt/Ti/SiO2/Si substrates by a sol-gel method. The enhanced ferroelectric properties and high energy-storage density have been achieved at 5% BiFeO3 substitution. Moreover, the 5% BiFeO3 doping Na0.5Bi0.5TiO3-BaTiO3 (0.89NBT-0.06BT-0.05BFO) thin-films exhibited a high dischargeable energy density (Wrecovered) of 42.9 J/cm3 with a corresponding energy-storage efficiency (η) of 65.7% under an electric field of 1720 kV/cm, and the high temperature stabilities with regard to their energy-storage properties over temperatures ranging from room temperature to 260 °C were demonstrated, and the charging and discharging characteristics demonstrate the faster microsecond discharge and large dielectric strength of the thin film capacitor. The results indicated that the 0.89NBT-0.06BT-0.05BFO thin-films might be promising environmentally friendly lead-free materials for energy-storage capacitor application.