Structural, electrical and energy storage properties of lead-free NaNbO3-BaHfO3 thin films

Abstract

Lead-free dielectric thin-film capacitors with desirable energy storage density are gathering attention due to the increasing environmental concern and the miniaturization of electronic devices. We here reported the new lead-free dielectric thin films, namely (1-x)NaNbO3-xBaHfO3 (x ≤ 0.15), prepared by a sol-gel method, and presented the dependence of their structural, electrical and energy storage properties on the x level of BaHfO3. The microstructure, leakage current and breakdown strength of pristine NaNbO3 thin films are significantly improved by addition of BaHfO3. As a result, the superior energy storage performances were obtained at x = 0.1 with recoverable energy storage density Wr of 23.1 J/cm3 at 1100 kV/cm, excellent thermal stability from 30 to 210 °C (ΔWr < 4.6%), good fatigue resistance (ΔWr < 2.9% after 104 electrical cycles), and the fast charge-discharge rate (τ = 0.82 μs ).