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Composition design of BNBT-ST relaxor ferroelectric ceramics in superparaelectric state with ultrahigh energy density.
- Source :
-
Ceramics International . Sep2023:Part A, Vol. 49 Issue 17, p27750-27757. 8p. - Publication Year :
- 2023
-
Abstract
- BNT-6BT-based lead-free ceramics have gained significant attention due to their relatively large piezoelectric coefficients and tunable morphotropic phase boundary conditions. In this investigation, SrTiO 3 (ST) was added to BNT-6BT ceramics to fabricate the BNT-6BT- x ST (BNBT- x ST) composition. The impact of ST content on the phase structure and dielectric permittivity of the BNBT- x ST ceramics was studied. The XRD refinement data show that with increasing ST content, the crystal structure of BNBT- x ST ceramics was transformed from the morphotropic phase structure (coexisting tetragonal (P4/mmm) and pseudo-cubic (Pmm) phase) to the pseudo-cubic phase. The dielectric permittivity data of the BNBT-80ST showed that the T m (the maximum permittivity temperature) moved to −61.9 °C, which caused the room temperature to fall within the range of T m < T < T B (the Burns temperature). This makes the BNBT-80ST a superparaelectric state in relaxor ferroelectrics (RFE). Furthermore, the maximum energy density and the charge-discharge efficiency of the BNBT-80ST achieved 5.48 J/cm3 and 87% at 495 kV/cm, respectively. The energy density of the BNBT-80ST was improved by 2.97-fold and 49% compared with that of the BNBT-30ST and BNBT-70ST. This is mostly attributed to weakened ferroelectricity and improved paraelectricity in the BNBT-80ST. This investigation demonstrates that BNBT- x ST ceramics can be adjusted to a superparaelectric state with an ST content of 80%. This makes the material to possess both a large polarization and a high breakdown field. This material holds great promise for high energy density capacitor applications. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02728842
- Volume :
- 49
- Issue :
- 17
- Database :
- Academic Search Index
- Journal :
- Ceramics International
- Publication Type :
- Academic Journal
- Accession number :
- 166739802
- Full Text :
- https://doi.org/10.1016/j.ceramint.2023.05.239