Tunning the dielectric and energy storage properties of high entropy ceramics (Bi0.2Na0.2K0.2La0.2Sr0.2)(Ti1-xScx)O3 by Sc-doping at B-site in perovskite structure

The (Bi0.2Na0.2K0.2La0.2Sr0.2)(Ti1-xScx)O-3 (BNKLST-xSc) high entropy ceramics (HECs) have been successfully synthesized via a citrate acid method. The effects of Sc-doping on the lattice structure, microstructural morphology, dielectric and energy-storage properties of HECs are comprehensively investigated. The results indicate that although Sc3+ doped at B-site does not alternate the perovskite structure of BNKLST with a single phase, it results in lattice expansion and weakened bonding in TiO6 octahedron. The dielectric constant of BNKLST-xSc is reduced while the dielectric relaxation is enhanced with increasing Sc content x, due to the enhanced structural inhomogeneity in nano-regions. In addition, the lattice structure of BNKLST-0.2Sc exhibits ultra-high thermal stability at 30-300 degrees C, which achieves the maximum energy storage density of 1.094 J/cm(3) with an outstanding efficiency better than 80%, accompanying by the mechanical and dielectric losses as low as similar to 10(-3). It is suggested that BNKLST-0.2Sc could be promising dielectric materials in capacitors and energy-storage devices with an excellent combination of ultrahigh power density, high energy density, thermal stability as well as low mechanical and dielectric losses.

Automated summary

The effects of Sc-doping on the lattice structure, microstructural morphology, dielectric and energy-storage properties of (Bi0.2Na0.2K0.2La0.2Sr0.2)(Ti1-xScx)O-3 (BNKLST-xSc) high entropy ceramics were investigated. The results show that Sc-doping leads to lattice expansion and weakened bonding in TiO6 octahedron, reducing dielectric constant but enhancing dielectric relaxation. Additionally, BNKLST-0.2Sc exhibits ultra-high thermal stability and excellent energy storage properties.