Significantly enhanced energy storage density with superior thermal stability by optimizing Ba(Zr_0.15Ti_0.85)O₃/Ba(Zr_0.35Ti_0.65)O₃ multilayer structure

Excellent thermal stability with high energy storage density in ultra-wide range of temperatures is the extremely important property of capacitors for applications in cold polar regions, extreme altitudes and high temperature regions. Here, we report on designing and preparing the BaZr_0.15Ti_0.85O₃/BaZr_0.35Ti_0.65O₃ (BZT15/BZT35) multilayer thin film capacitors. Under a given total thickness, the energy storage performances of the multilayer films can be optimized by controlling the number of interfaces. For the capacitor with an optimum period number N = 6, the markedly enhanced breakdown strength and large dielectric constant are achieved, which leads to a giant energy storage density (W_re) of ~83.9 J/cm³ with the efficiency (η) of ~78.4% and a superior power density of 1.47 MW/cm³ at room temperature. Moreover, the N = 6 multilayer capacitor also exhibits ultra-stable W_re of 69.1 J/cm³ (efficiency: 84.9%) to 63.2 J/cm³ (efficiency: 66.9%) from − 100 °C to 200 °C and a good reliability in W_re and η even after 10⁶ cycles at 200 °C. The excellent performances demonstrate that the multilayer films are a promising material system to meet the wide requirements of future applications, ranging from portable electronics to hybrid electric vehicles and aerospace power electronics.