Dielectric properties and energy-storage performance of (Na0.5Bi0.5)TiO3-SrTiO3 thick films derived from polyvinylpyrrolidone-modified chemical solution

In this work, the 1.5-μm (1 − x%)(Na0.5Bi0.5)TiO3-x%SrTiO3 (abbreviated as NBT-xST, x = 0, 5, 10 and 15) thick films were successfully fabricated on LaNiO3/Si (1 0 0) substrate by using a polyvinylpyrrolidone-modified chemical solution route. The effect of SrTiO3 (abbreviated as ST) content on the dielectric properties and energy-storage performances of the thick films were investigated in detail. It was found that the addition of ST enhanced the breakdown strength (BDS) and improved the difference between the maximum polarization (Pmax) and the remnant polarization (Pr) of the thick films. The maximum recoverable energy-density (W) of 36.1 J/cm3 and the corresponding efficiency (η) of 40.8% were obtained in NBT-5ST thick film, which also displayed good energy-storage stability in the temperature range from room temperature to 80 °C. Moreover, under the external electric field of 500 kV/cm, NBT-5ST thick film showed the low leakage current density of 1.93 × 10−5 A/cm2 at room temperature. The results indicated that NBT-xST thick films might be promising environmentally friendly lead-free materials for energy-storage capacitor application.