Combining high energy efficiency and fast charge-discharge capability in calcium strontium titanate-based linear dielectric ceramic for energy-storage

Abstract

The high energy density and power density dielectric ceramics with wide frequency and temperature stability are competitive materials for pulse power capacitors. This research proposes an effective strategy for enhancing energy storage performance of Ca0.5Sr0.5TiO3 ceramics through the introduction of Sn4+ ion. This ion restrains grain growth, increases high insulating grain boundaries, and thus enhances the barrier height of grain boundaries, which are demonstrated in SEM micrographs and complex impedance. The Ca0.5Sr0.5Ti0.97Sn0.03O3 (SnCST3) ceramics possess high energy storage density of 2.06 J/cm3 and efficiency of 95% under breakdown strength of 330 kV/cm, which get benefit from wide band gap of 5.3 eV. While the exceptional stability with minimal fluctuation (<15%) in the wide frequency range of 1–1000 Hz and temperature range of 20–120 °C are also achieved in this system. Furthermore, the pulse discharge performance are performed to appraise practical applications of pulse power capacitors. The prominent power density of 32.2 MW/cm3 and current density of 537.4 A/cm2 are obtained. Meanwhile, stored energy are released in very short duration of 13 ns as well as outstanding temperature stability is realized in the temperature range of 20–120 °C for the SnCST3 ceramic, confirming it as one competitor for lead-free high power capacitors.