Deposition of Sm0.5Sr0.5CoO3 (SSC) films on Gd-doped ceria (GDC) substrates by electrostatic assisted ultrasonic spray pyrolysis (EAUSP) was demonstrated in this study. The XRD results indicate that crystalline phase with perovskite structure was obtained in the calcined films. SEM observations indicate that applied voltage and deposition temperature have profound effects on the film morphology in EAUSP method. Stronger applied voltage results in the smoother film while higher deposition temperature results in rougher film. A unique thick porous film with column structure is obtained for the first time by EAUSP method using a deposition temperature of 400 oC, an applied voltage of 10 kV and a deposition time of 600 seconds. The growth mechanism of the unique porous thick film is also discussed in this study. The area specific resistance (ASR) values of SSC cathode with this unique porous columnar structure are comparable to that obtained by conventional sample preparation routes. For example, an ASR value of 0.204 £[¡Ecm2 at 600 oC is obtained in this work.
Electrostatic spray deposition (ESD) method was also employed to deposit SSC films as cathode on GDC substrates in this study. Crystalline SSC with perovskite structure was obtained in the calcined films. Deposition parameters including deposition temperature, precursor flow rate and deposition time were systematically varied to obtain the SSC films with various morphologies. The best film structure for high electrochemical performance is a porous reticular structure obtained under a precursor solution flow rate of 2.0 ml/hr and a deposition temperature of 350 oC. The growth mechanism of this reticular structure is established based on the examination of film evolution in a series of films obtained with different deposition times. The minimum ASR value of the porous reticular SSC cathode fabricated by ESD is 0.09 £[¡Ecm2 at 600 oC.
SSC nano-wires were successfully synthesized by electro-spinning method. The diameter of calcined nano-wires ranges from 40 to 90 nm. The TEM results indicate that the calcined (800oC/2hr) SSC nano-wires are polycrystalline with an orthorhombic perovskite structure. SSC nano-fibers were then obtained from the SSC nano-wires through an ultrasonic vibration of 15 minutes. Electrodes of SSC nano-fiber on GDC substrate were then prepared by slurry printing method. The ASR values of SSC nano-fiber electrodes are extremely low and the minimum ASR value is 0.06 £[¡Ecm2 at 600 oC.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0831109-151248 |
| Date | 31 August 2009 |
| Creators | Chang, Chun-Liang |
| Contributors | Pi-Chuen Tsai, Jenn-Shing Chen, Che-Wun Hong, Bing-Hwai Hwang, Herng-Yih Ueng |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0831109-151248 |
| Rights | not_available, Copyright information available at source archive |
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