Boosting up the capacitive energy storage performances of lead-free ceramics via grain engineering for pulse power applications

Abstract Exploring high-performance ceramics has been a great challenge for advanced electronic devices due to their limited capacitive energy storage densities in high-voltage pulse applications. The refinement of the microstructures can considerably optimize energy storage performances of dielectric ceramics by tailoring dielectric breakdown. Here, two-step sintering was employed to refine the microstructures of the lead-free 2.0 mol% Mn-doped 0.55 (0.94Na0.5Bi0.5TiO3-0.06BaTiO3)-0.45SrTiO3 bulk ceramics to offer the possibility of increasing energy storage performances. Compared with conventional sintering, fine grains by two-step sintering can be obtained, resulting in the obviously enhanced dielectric breakdown due to the increased fraction of grain boundary and the suppressed movement of domain walls. An ultrahigh charge energy storage density of 2.98 J/cm3 with a moderate efficiency (η) of 73.1% can be achieved at 28 kV/mm, accompanying with excellent temperature insensitivity in a wide range from 30 to 180 °C compared with the previous Na0.5Bi0.5TiO3-based derivatives. This work presented here strongly indicates that two-step sintering is a promising way to optimize the microstructural morphology and electrical performances of dielectric ceramics.