Enhanced Energy-Storage Properties of Ta Modified BNT − BT − NN Lead-Free Ceramics

Abstract

Lead-free 0.9(0.92Bi_0.5Na_0.5TiO₃–0.08BaTiO₃)–0.1(NaNb_(1-x)Ta_xO₃) ceramics (abbreviated as BNBT − NN_1-xT_x), x = 0, 0.25, 0.50, 0.75 and 1.00, were prepared by conventional solid-state mixed oxide route. The effects of Ta substitution on the crystal structure, morphology, dielectric, ferroelectric as well as energy-storage properties were systematically investigated. X-ray diffraction revealed a single-phase perovskite structure for x ≤ 0.75 with coexisting rhombohedral and tetragonal phases. With increasing Ta substitution, a weakening of tetragonal distortion was observed. The SEM micrographs of all samples displayed dense microstructure with an average grain size of 0.70–0.99 µm. Good temperature stability of dielectric properties was maintained in the whole range of Ta substitution. The composition with x = 0.25 showed an optimum energy-storage density of 0.37 J/cm³ and the energy-storage efficiency of 75.1% at 50 kV/cm, thus indicating the promising application of BNBT–NN_1-xT_x ceramics as energy-storage capacitors.

Keywords:

• BNT-BT
• energy storage properties
• lead-free
• dielectric properties

Acknowledgements

The authors would also like to thank Dr. Nitish Kumar and Michelle Jennings for helps in editing the language of the manuscript.

Additional information

Funding

This work was financially supported by faculty of science, Naresuan University.