PREPARATION AND CHARACTERIZATION OF CATHODE MATERIALS FOR LITHIUM ION SECONDARY BATTERIES AND LUMINESCENT MATERIALS FOR FIELD EMISSION DISPLAYS
Date Issued
2006
Date
2006
Author(s)
Wu, Tai-Yuan
DOI
en-US
Abstract
Li1.03Co0.15Mn1.82O4 powders as cathode materials used in lithium-ion battery were synthesized using an ultrasonic spray pyrolysis process. As the time increased at 750oC heating, the crystallinity of the powders enhanced. The nanometered primary particles were aggregated into sphere-like secondary particles. The surface area of the heated samples decreased with an increase in the heating time. During the high C-rate tests, the sample heated for 4 h revealed 87% capacity retention at 60C-rate related to 0.1C. The electrochemical performance of the prepared Li1.03Co0.15Mn1.82O4 powders depends on not only the crystallinity but also the surface area. The sample heated for 4 h may fit this requirement and it exhibited good rate capability.
Secondly, Sr2CeO4 phosphors were prepared via the microwave-assisted solvothermal method with post-heating. The blue emission was obtained under an excitation wavelength of 280 nm. Compared with the solid-state method, the powder derived by the microwave-polyol method had higher luminescence intensity. Deconvoluted excitation and emission spectra were also investigated in order to analyze the band structure of Sr2CeO4. Smaller Stokes shift of microwave-derived powders were also observed.
Finally, ZnO:Zn phosphors were coated with SiO2 in order to modify the particle surface. The photoluminescence properties show a great enhancement due to the surface passivation. For further coatings the intensity decreased. The cathodoluminescence results showed a different trend. The depletion region of the particle surface determines the CL intensity.
Subjects
鋰電池
陰極材料
螢光材料
鈰酸鍶
氧化鋅
Li-ion batteries
cathode materials
phosphors
Sr2CeO4
ZnO
SDGs
Type
thesis
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