Interface thickness optimization of lead-free oxide multilayer capacitors for high-performance energy storage

The effects of interface density and total multilayer film thickness on the dielectric properties and breakdown behavior have been revealed in this work by investigating the environment-friendly energy storage multilayer films of Ba_0.7Ca_0.3TiO₃ (BCT) and BaZr_0.2Ti_0.8O₃ (BZT) dielectrics. Numerical simulations based on a finite element method have given the breakdown process vividly, which agreed well with the experimental results. Moreover, not only the ultrahigh energy storage density of 51.8 J cm^-3 with a great efficiency of 81.2% at room temperature but also robust thermal stability has been obtained by optimizing the interface density and total thickness. High energy density above 25.1 J cm^-3 and excellent efficiency over 63.6% from room temperature to 200 °C provide a solid basis for potential applications of the multilayer systems in harsh environments.