Superior energy storage properties of (1-x)Ba<inf>0.85</inf>Ca<inf>0.15</inf>Zr<inf>0.1</inf>Ti<inf>0.9</inf>O<inf>3</inf>-xBi(Mg<inf>2/3</inf>Ta<inf>1/3</inf>)O<inf>3</inf> lead-free ceramics

Abstract

In this work, lead-free (1-x)Ba0.85Ca0.15Zr0.1Ti0.9O3-xBi(Mg2/3Ta1/3)O3 (BCZT-BMTx) relaxor ferroelectrics (RFEs) were prepared via a traditional solid-state reaction. BMT was introduced into ferroelectric (FE) BCZT ceramics by a strategy of composition modification, which remarkably inhibited the grain growth and triggered a FE-to-RFE phase transition. The breakdown strength (Eb) of BCZT ceramics was greatly improved by enhancing the band gap with Ta2O5 (∼4 eV) doping into B-site. BCZT-BMT8 ceramic possesses both high energy efficiency (η) of 93.87% and recoverable energy density (Wrec) of 3.4 J/cm3 at a relatively high Eb of 440 kV/cm, which are superior to most of other BaTiO3-based energy storage ceramics. Especially, excellent energy storage stability with respect to frequency (2–500 Hz, a variation of Wrec<4.27% and η < 2.65%) and temperature (30–130 °C, Wrec<13.5% and η < 2.4%) was obtained for BCZT-BMT8 ceramic. In brief, the enhanced Wrec and Eb with significantly high η indicated that BCZT-BMT8 ceramic is a promising candidate for energy storage capacitors.