This thesis work is focused on the study of oxides in form of nanostructured samples for functional applications. These applications take advantage of their high mechanical and chemical stability, high melting point, electric, optical, and magnetic properties. In particular the work is divided in three parts, which represent the three different functional applications studied: magnetic materials, protonic conductors, and lithium-ion batteries cathodes. For the magnetic materials, CoFe2O4 nanostructured sintered samples were studied in their magnetic properties, leading to interesting values. The magnetic parameters have been evaluated in sintered sample having different type of microstructure, relative density, and grain size. The protonic conductors studied are TiO2, CeO2 and ZrO2 doped with sulfur. The nanostructured sintered samples of these oxides were evaluated in their protonic conduction properties, the protonic conductivity has been evaluated in this oxide at different values of relative humidity. The results are that S-TiO2 and S-ZrO2 showed very good conductivity values, instead S-CeO2 presented values of conductivity not so good to be applied as protonic conductor. Finally new materials in form of high-entropy oxides were tried to synthesize in order to obtain new cathodes nanostructured oxides for Li-ion batteries, having the same crystal structure of LiMn2O4 but with the substitution of some cations on the MnIII and MnIV sites. Different trivalent and tetravalent cations have been used in order to enter in the spinel structure and lead to an enlargement of the spinel unit cell: Y3+, Fe3+, Al3+, Cr3+, In3+, Ti4+, Zr4+, Tb4+. Some interesting compounds, as LiFe0.6Ti0.6Mn0.8O4, LiFe0.7Mn0.6Ti0.7O4, LiFe0.5Mn0.5TiO4 and LiFe0.5Ti0.5MnO4 were synthesized.
|Titolo:||SYNTHESIS AND CHARACTERIZATION OF BULK NANOSTRUCTURED OXIDES FOR FUNCTIONAL APPLICATIONS|
|Data di pubblicazione:||9-apr-2021|
|Appare nelle tipologie:||8.01 Tesi di dottorato|
File in questo prodotto:
|Baldini_Synthesis and characterization of bulk nanostructured oxides for functional applications.pdf||TESI FINALE||Tesi di dottorato||Open Access Visualizza/Apri|