Novel barium titanate based capacitors with high energy density and fast discharge performance

Recently, dielectric capacitors have attracted much attention due to their high power density based on fast charge-discharge capability. However, their energy storage applications are limited by their low discharge energy densities. In this work, we designed novel lead-free relaxor-ferroelectric 0.88BaTiO₃-0.12Bi(Li_0.5Nb_0.5)O₃ (0.88BT-0.12BLN) ceramics with high breakdown strength and high discharge energy density. The 0.88BT-0.12BLN ceramics were prepared by a conventional solid state reaction method. Optimal energy storage properties were obtained in 0.88BT-0.12BLN ceramics sintered at 1220 °C with an impressive discharge energy density of 2.032 J cm^-3 and a charge-discharge efficiency of beyond 88% at 270 kV cm^-1. The energy storage properties of the 0.88BT-0.12BLN also displayed good thermal stability from 20 to 120 °C at an electric field of 150 kV cm^-1. Moreover, the discharge speed behavior was investigated by using pulsed current. The pulsed discharge current waveforms showed that all the samples have fast discharge times (less than 0.5 μs) under different electric fields. This work significantly increases the intrinsic breakdown strength and discharge energy density of BaTiO₃-based materials with high charge-discharge efficiency for high power energy storage devices.