Linear-like lead-free relaxor antiferroelectric (Bi0.5Na0.5)TiO3-NaNbO3 with giant energy-storage density/efficiency and super stability against temperature and frequency

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 7; no. 8; pp. 3971 - 3978
• Main Authors: Qi, He, Zuo, Ruzhong
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 19.02.2019
• Subjects: ambient temperature; Antiferroelectricity; Ceramics; Data processing; Density; Efficiency; electric field; Electric fields; Electric power systems; energy; Energy storage; Ferroelectric materials; Frequency ranges; High temperature; hysteresis; Hysteresis loops; Lead free; Permittivity; phase transition; Phase transitions; Polarization; Power efficiency; Raman spectra; Raman spectroscopy; Relaxors; Solid solutions; Temperature dependence; Temperature effects; Temperature measurement; Transmission electron microscopy; X-ray diffraction
• ISSN: 2050-7488; 2050-7496; 2050-7496
• DOI: 10.1039/c8ta12232f

A novel lead-free polar dielectric ceramic with linear-like polarization responses was found in (1 − x )(Bi 0.5 Na 0.5 )TiO 3 - x NaNbO 3 ((1 − x )BNT- x NN) solid solutions, exhibiting giant energy storage density/efficiency and super stability against temperature and frequency. High-resolution transmission electron microscopy, Raman scattering and Rietveld refinements of X-ray diffraction data suggest that these property characteristics can be derived from temperature and electric field insensitive large permittivity as a result of relaxor antiferroelectricity (AFE) with polar nanoregions. Additionally, this feature intrinsically requires a high driving field for AFE to ferroelectric (FE) phase transitions due to large random fields. Measurements of temperature-dependent permittivity and polarization versus electric field hysteresis loops indicate that the high-temperature AFE P 4 bm phase in BNT was gradually stabilized close to room temperature, accompanying a phase transition from relaxor rhombohedral FEs to relaxor tetragonal AFEs approximately at x = 0.15-0.2. A record high of recoverable energy-storage density W ∼ 7.02 J cm −3 as well as a high efficiency η ∼ 85% was simultaneously achieved in the x = 0.22 bulk ceramic, which challenges the existing fact that W and η must be seriously compromised. Furthermore, desirable W (>3.5 J cm −3 ) and η (>88%) with a variation of less than 10% can be accordingly obtained in the temperature range of 25-250 °C and frequency range of 0.1-100 Hz. These excellent energy-storage properties would make BNT-based lead-free AFE ceramic systems a potential candidate for application in pulsed power systems. A novel lead-free polar dielectric ceramic with linear-like polarization responses was found in (1 − x )(Bi 0.5 Na 0.5 )TiO 3 - x NaNbO 3 ((1 − x )BNT- x NN) solid solutions, exhibiting giant energy storage density/efficiency and super stability against temperature and frequency.