Colossal dielectric permittivity and high energy storage efficiency in barium strontium titanate ceramics co-doped with bismuth and lithium

Abstract The development of energy storage devices in lead-free perovskite materials is critically important in addressing the environmental issues of perovskite lead. In this article, for the first time, lead-free (Ba 0.60 Sr 0.40 ) (1− x ) (Bi,Li) x TiO 3 , abbreviated as (BST6:BL x %); (0%⩽ x ⩽ 8%) ceramics, have been successively synthesized via the conventional solid-state reaction method. The structural evolution, dielectric and energy storage properties, as functions of co-doping levels, were systematically studied by x-ray diffraction, x-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy, scanning electron microscopy, impedance analyzer, and a Radiant Precision Premier II Analyzer. It was found that a small amount of co-dopants induced a colossal permittivity (CP) (over 10 5 ) with low loss (<0.1), a maximum energy storage density of 0.3856 J cm −3 with a BDS of ∼100 kV cm −1 , and an efficiency of over 90%. The defects and chemical state of the elements contained in the material’s surface were investigated using XPS. In conjunction with the results of XPS and complex impedance studies, the mechanism of massive permittivity was interpreted based on a defect-dipole model. We believe that BST6:BL x % ceramics, as CP and high energy storage efficiency materials, might be considered a promising candidate for high energy storage applications.