Synthesis and Characterization of KNN Modified BNT-ST Ceramics for Energy Storage Applications

Abstract

Lead-free [(0.76-x)Bi_0.5Na_0.5TiO₃–0.24SrTiO₃–x(K_0.5Na_0.5)NbO₃; BNT-ST-KNN] ceramics with x = 0, 0.03, 0.05, 0.07, 0.10, 0.15 wt.% were synthesized by using a solid-state reaction method. The effect of x content on phase, microstructure electrical and energy density properties was investigated. The samples were analyzed by X-ray diffraction (XRD) and the XRD patterns were fitted using the Rietveld refinement. The grain growth is obviously inhibited and smaller grains are formed in the ceramic samples at a high concentration of x. Dielectric study confirmed relax or nature with a drastic decrease of T_max with the increase of x content in BNT-ST-KNN system. The maximum density (ρ = 5.42$\pm$0.13 g/cm³), highest dielectric constant (ε_r=3300) with tanδ∼0.05, high recoverable energy storage density (W_rec=0.16 J/cm³) with energy storage efficiency of (η = 64) were obtained in x = 0.03 wt.% ceramic samples, which suggested its usefulness for energy-storage capacitor applications.

KEYWORDS:

• Energy storage density
• lead-free
• dielectric properties
• BNT-ST-KNN

Acknowledgments

The authors wish to thank the Faculty of Science and Technology, Pibulsongkram Rajabhat University is also supported. Thanks are given to Dr. Nitish Kumar for his help in editing the manuscript.

Additional information

Funding

This work financially supported by the Thailand Science Research and Innovation (TSRI) (Grant no. MRG6280153).