YBCO as a transition metal oxide ceramic material for energy storage

• Published in: Bulletin of the National Research Centre Vol. 43; no. 1; pp. 1 - 11
• Main Authors: Salama, A. H., Youssef, A. M., Rammah, Y. S., El-Khatib, M.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 07.06.2019; Springer Nature B.V; SpringerOpen
• Subjects: Ac electrical conductivity; Capacitors; Ceramics; Chromium oxides; Cobalt oxides; Composite materials; Conduction; Correlation analysis; Dielectric constant; Dielectric loss; Dielectric properties; Dispersion; Electrical conductivity; Electrical properties; Electrical resistivity; Electrodes; Energy storage; Ferroelectric materials; Ferroelectricity; Frequency dependence; High temperature superconductors; High-temperature superconductor; Hopping conduction; Humanities and Social Sciences; Low frequencies; Magnetic moments; Manganese oxides; Metal oxides; Metals; multidisciplinary; Oxides; Permittivity; Perovskites; Room temperature; Science; Science (multidisciplinary); Super dielectric materials; Temperature; Transition metal oxides; YBCO superconductors; Ac electrical conductivity; Super dielectric materials; High-temperature superconductor; Dielectric properties
• ISSN: 2522-8307; 2522-8307
• DOI: 10.1186/s42269-019-0134-6

Background Dielectric properties and ac conductivity were studied and correlated with the structure of a series of YBCO ceramic, doped with different doping levels ranging from 0.1 to 0.5 wt.% of magnetic nano-metal oxides, namely Mn 3 O 4 , Co 3 O 4 , and Cr 2 O 3 . The most important feature of this study was the ultrahigh values of dielectric constants at a low frequency, exactly 50 Hz. We found that the undoped YBCO has a value of ε′ equal to 6.99 × 10 6 at 50 Hz at room temperature which was increased to 1.09 × 10 8 at 120 °C, higher than any other ferroelectric material. Moreover, the value of ε′ depends on the nature and the value of the magnetic moment of the doped metal oxides. The value of ε′ is at least three orders of magnitude greater than any previously studied composites which suggest that this perovskite ceramic material can be used to create electrostatic capacitors with energy far better than the best electrode double-layer capacitors (EDLC). Additionally, ac electrical conductivity has two frequency-dependent regions, the low frequency, where σ ac is independent of frequency, and the high-frequency region where dispersion occurs. The ac conductivity measurement with frequency leads us to conclude that the conduction mechanism in the studied samples can be correlated barrier hopping (CBH) model. Results The dielectric properties of undoped YBCO ceramics at 50 Hz in temperature ranging from room temperature to 120°C were studied. It is obvious that the dielectric constant and dielectric loss of YBCO decrease with increase in frequency and temperature. It can be noticed that dielectric constant of YBCO increases at 50 Hz from 6.99 × 10 6 at room temperature to 1.09 × 10 8 at 120°C. The high values of ε′ recorded for YBCO doped with Mn 3 O 4 varied from 9.45 × 10 5 to 15.5 at room temperature and 1.34 × 10 5 to 9.242 at 1 MHz at 120°C. For doped YBCO with Co 3 O 4, the values of ε\ varied from 9.5 × 10 5 at 50 Hz to 13.24 at 1 MHz at room temperature, with changes from7.8 × 10 4 at 50 Hz to 53.42 at 1 MHz. For YBCO ceramic samples doped with Cr 2 O 3, ε′ varied from 1.138 × 10 6 at 50 Hz to 8.38 × 10 3 at 1 MHz at room temperature and from 5.935 × 10 5 at 50 Hz to 3.53 × 10 3 at 1 MHz at 120°C. The ac conductivity was further studied for undoped YBCO and doped YBCO with 0.1 wt.% of nano-metal oxide of Cr 2 O 3 , Co 3 O 4 , and Mn 3 O 4 samples. For all the studied samples, we found σ ac is typically specified to the hopping conduction and ac conductivity has a power law behavior in terms of frequency (ω). In general, there are two frequency-dependent regions for all the studied ceramic samples; in the low-frequency region, σ ac is independent of frequency whereas in the high-frequency region, dispersion occurs. The change in microwave conductivity of the studied samples with frequency (1–5 MHz) is shown in Fig. 5. It is observed that for all samples, the conductivity increases with temperatures and depends on the doped metal oxide. The values of σ ac at 5 MHz varied from − 0.4 to 1.2 for undoped YBCO, from − 0.98 to − 0.75 for 0.1 wt.%Mn 3 O 4 -YBCO sample, from − 0.25 to 0.2 for 0.1 wt.% Co 2 O 3 -YBCO sample, and from − 0.4 to 0.6 for 0.1 Wt.% Cr 3 O 4 -YBCO sample. Conclusion The primary finding in this paper is of empirical investigation. YBCO, which is a high-temperature superconductor, has a high dielectric constant ε′ ranging from 6.99 × 10 6 at room temperature to 1.09 × 10 8 at 120°C. This value is at least three orders of magnitude greater than any previously studied composites which suggest that this perovskite ceramic material can be used to create electrostatic capacitors with energy far more efficient than the best electrode double layer capacitors (EDLC).