Fine-grained silica-coated barium strontium titanate ceramics with high energy storage

Abstract

The fine-grained silica-coated Ba0.3Sr0.7TiO3 (BST) ceramics were prepared by conventional solid-phase sintering method, the size of matrix materials which were produced by oxalate co-prepared method is about 100 nm. With the increase of the content silica, the grain size of ceramic dropped from 2 µm (pure BST) to 300 nm (Ba0.3Sr0.7TiO3-3 wt% SiO2) and the polarization of ceramic decreased under the same applied electric field, but the energy storage efficiency increased significantly. At the same time, the dielectric breakdown strength (BDS) increased significantly with the decrease of grain size and the addition of SiO2. For Ba0.3Sr0.7TiO3-3 wt% SiO2 ceramic, due to the small grain size, the BDS increased from 130 kV/cm to 380 kV/cm, its discharge energy storage density is 1.52 J/cm3 while the energy storage efficiency reaches 82.2%. The discharge energy density of the Ba0.3Sr0.7TiO3-3 wt% SiO2 ceramic increased to 3.3 times than that of pure Ba0.3Sr0.7TiO3 ceramic.