Ultra-high energy storage density and enhanced dielectric properties in BNT-BT based thin film

Abstract

In this work, Mn modified 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 thin films (abbreviation for BNT-BT-Mnx) are prepared on Pt/Ti/SiO2/Si substrate via sol-gel and spin-coating. The influences of Mn dopant on the microstructural characteristics, dielectric and energy storage performances are studied systematically. It is found that by incorporating the Mn into BNT-BT, the breakdown strength and maximum polarization are enhanced dramatically, leading to the giant energy storage density of 54 J/cm3, with high permittivity 355 at 1 kHz. Moreover, the dominant leakage conduction mechanisms of the thin films are studied by linear fitting method, revealing that the leakage current mechanism of BNT-BT-Mnx films transforms from space-charge-limited conduction (SCLC) to Schottky emission as the increasing of electric field. The excellent energy storage density as well as dielectric properties suggest that BNT-BT-Mn6 thin film might be an attractive lead-free material for energy storage devices.