Lead-free Ba2Bi4Ti5O18 thin film capacitors for energy storage applications

Abstract

Lead-free Ba2Bi4Ti5O18 thin film belongs to Aurivillius phase are fabricated on Pt/Ti/SiO2/Si substrates by chemical solution deposition and the ferroelectric, leakage and dielectric are investigated. The derived film shows dielectric constant of 260 at 1 MHz and low leakage current density of 9.4 × 10−6 A/cm2 at 500 kV/cm, respectively. Interestingly, benefit from the large spontaneous and high breakdown electric field, the obtained slim electric field-polarization curve endows large energy storage density (22.6 J/cm3) and high storage efficiency (71.3%) in the Ba2Bi4Ti5O18 capacitors. Additionally, the insignificant decrease of energy storage density (3.5%) and efficiency (2.4%) is obtained after 9.8 × 109 charging-discharging cycling, which indicate senior fatigue endurance property of the film capacitor. Those results not only suggest that Ba2Bi4Ti5O18 thin film have good potential applications as the dielectric energy storage capacitors, but also provide an important clue to further explore isostructural materials in the Aurivillius family compounds. Keywords: Ba2Bi4Ti5O18, Dielectric capacitors, Energy storage