Excellent energy storage performance of (ScTa) modified (BiNa)TiO-based ceramics modulated by the evolution of polar phases

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 11; no. 26; pp. 14169 - 14179
• Main Authors: He, Bin, Ochirkhuyag, Tumentsereg, Feng, Wuwei, Liu, Meitang, Liu, Shuo, Bao, Zhidi, Hu, Cheng, Zhong, Yi, Odkhuu, Dorj
• Format: Journal Article
• Published: 04.07.2023
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d3ta01172k

To address the environmental pollution and energy crisis in the world, the next generation of advanced pulsed power capacitors has been developed rapidly in recent years, which require lead-free dielectric ceramics with excellent energy storage performance. Herein, we propose a strategy to optimize the energy storage performance of (Bi 0.5 Na 0.5 )TiO 3 -based ceramics via exploring a high saturation polarization which could be modulated by the evolution of oxygen vacancies and local polar phases induced by chemical modification. A high saturation polarization could be maintained in (Sc 0.5 Ta 0.5 ) 4+ doped (Bi 0.5 Na 0.5 )TiO 3 -0.30SrTiO 3 (BNST) ceramics, which is ascribed to the increased content of the rhombohedral phase with higher polarization anisotropy. Besides, the incorporation of (Sc 0.5 Ta 0.5 ) 4+ also concurrently induces smaller-sized polar nano-regions and widens the band gap, thereby achieving a stronger relaxor state and larger breakdown electric field. As a result, an ultrahigh recoverable energy density W rec of 12.2 J cm −3 , an excellent efficiency of 85.9%, and superior energy storage thermal stability ( W rec = 4.4 ± 0.1 J cm −3 , η = 89.9 ± 0.9%, 20-140 °C) are obtained in the 20 mol% (Sc 0.5 Ta 0.5 ) 4+ doped BNST ceramic. The present experimental and theoretical systematic studies provide a novel avenue and paradigm for the development of dielectric ceramic materials with ultrahigh energy storage properties. An ultrahigh energy storage performance is achieved in the BNST-20% (Sc 0.5 Ta 0.5 ) 4+ ceramic via chemical modification, which could induce the evolution of oxygen vacancies and local polar phases to achieve a high saturation polarization.