Large Energy Density, Excellent Thermal Stability, and High Cycling Endurance of Lead-Free BaZrTiO Film Capacitors.

A large energy storage density (ESD) of 30.4 J/cm and high energy efficiency of 81.7% under an electrical field of 3 MV/cm was achieved at room temperature by the fabrication of environmentally friendly lead-free BaZrTiO epitaxial thin films on Nb-doped SrTiO (001) substrates by using a radio-frequency magnetron sputtering system. Moreover, the BZT film capacitors exhibit great thermal stability of the ESD from 16.8 J/cm to 14.0 J/cm with efficiency of beyond 67.4% and high fatigue endurance (up to 10 cycles) in a wide temperature range from room temperature to 125 °C. Compared to other BaTiO-based energy storage capacitor materials and even Pb-based systems, BaZrTiO thin film capacitors show either high ESD or great energy efficiency. All of these excellent results revealed that the BaZrTiO film capacitors have huge potential in the application of modern electronics, such as locomotive and pulse power, in harsh working environments.