The Preparation and Characterization of α-LiFeO2-based and Goethite-type LiFeO2-based Cathode Materials
| Autor: | Hsin-yen Liu, 劉炘彥 |
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| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 α-LiFeO2-based and goethite-type LiFeO2 powders were prepared with ion-exchanging method by using β-FeOOH and α-FeOOH as precursors those were derived from the hydrolysis of FeCl3 and FeCl2 in aqueous solutions, respectively. Among the lithium salts those are soluble in ethanol; LiOH had been proved as the most effective ion-exchanging salt. The composition, the crystalline structure, and the morphology of the prepared powders are determined with ICP, XRD, and SEM, respectively. The electrochemical properties, reaction occurred, and structure change upon cycling are investigated with capacity retention study, cyclic voltammetry, in-situ XANES, and in-situ XRD. The nano-sized α-LiFeO2-based powders prepared in the study are electrochemical active and exhibit reversible capacities ranging between 50 and 80 mAh/g due to the reaction of Fe2+/Fe3+ redox couple. Nano-sized α-FeOOH and goethite-type LiFeO2-based powders prepared by having α-FeOOH ion-exchanged with LiOH in ethanol solution exhibit poor cycleability and low specific capacity in Fe2+ ⇋ Fe3+ redox reaction, respectively. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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