Research Of The Hollow Fiber Solid Oxide Fuel Cell

Solid oxide fuel cell (SOFC) is a kind of device that convert the chemical energy in thechemical fuels into electrical energy directly, environmentally friendly and efficiently. Themicro tubular solid oxide fuel cell with outer diameter at the millimeter scale possesses lowoperation temperature, excellent performance of resistance of thermal cycling, rapid start-upability and higher volume power density. Up to now, the most common techniques forpreparation micro tubular SOFCs are cold isostatic pressing, extrusion and casting. Phaseinversion/spinning has been recently employed for the fabrication of hollow fber SOFCs(HF-SOFCs), which provides a rapid fabrication process and better control of themicrostructure. In this dissertation, we adopt the phase inversion/spinning/co-sinteringprocess and the dip-coating and brush painting method to prepare the linearelectrolyte-supported HF-SOFC NiO-YSZ/YSZ/YSZ-LSM/LSM, linear anode-supportedHF-SOFC NiO-YSZ/YSZ/PLNCG, linear anode-supported HF-SOFC NiO-GDC/GDC/PLNCG, U-shaped anode-supported HF-SOFC NiO-YSZ/YSZ/YSZ-LSM/LSM and linearanode-supported HF-SOFC NiO-YSZ/YSZ/YSZ-LSM/LSM。After fixing all kinds of theHF-SOFC single cells, we conduct the test of their electrochemical performance. The mainresearch contents of this dissertation are displayed as follows:Firstly, we successfully fabricate the linear YSZ electrolyte hollow fiber support withasymmetric structure by phase inversion/spinning/co-sintering method. The inner side of theYSZ electrolyte hollow fiber is the finger-like structure, proving the deposition location of theNiO-YSZ anode and enlarging the anode triple phase boundries. The outer side of the YSZelectrolyte hollow fiber is the sponge-like structure, after sintering at certain temperature, itcan form a very thin layer, which both prevent the mutual diffusion of the H2at anode and theO2at cathode and reduce the resistance of the conductivity of O2-. Based on the YSZelectrolyte support, we successfully fabricated the linear electrolyte-supported HF-SOFCNiO-YSZ/YSZ/YSZ-LSM/LSM. The maximum power density of the cell is0.2mW cm-2at750oC.Secondly, we successfully fabricate the linear NiO-YSZ anode hollow fiber support withasymmetric structure by phase inversion/spinning/co-sintering method, the inner side ofwhich is the finger-like structure and the outer side of which is the sponge-like structure.Based on the NiO-YSZ anode support, we successfully fabricate the linear anode-supportedHF-SOFC NiO-YSZ/YSZ/PLNCG. The cell manifests good electrochemical performance, themaximum power density is876mW cm-2and the polarization resistance is0.41Ω cm~2at750 oC. Moreover, the PLNCG cathode shows good CO2resistance in the intermediatetemperature range.Thirdly, we successfully fabricate the linear NiO-GDC anode hollow fiber support withasymmetric structure by phase inversion/spinning/co-sintering method, the inner side ofwhich is the finger-like structure and the outer side of which is the sponge-like structure. TheXRD patterns reveal that the PLNCG cathode shows good chemical compatibility with theGDC electrolyte when the temperature is not higher than900oC. Based on the NiO-GDCanode support, we successfully fabricate the linear anode-supported HF-SOFCNiO-GDC/GDC/PLNCG. The cell manifests good electrochemical performance, themaximum power density is109mW cm-2and the polarization resistance is0.98Ω cm~2at550oC.Fourthly, we successfully fabricate the U-shaped NiO-YSZ anode hollow fiber supportby phase inversion/spinning/co-sintering method, the inner side of which is the finger-likestructure, providing the deliver channels for the importing of the H2fuel gas and exporting ofthe product vapor; the outer side of which is the sponge-like structure, containing the anodetriple phase boundries, providing the reaction sites for the catalytic oxidation of the H2in theanode. Based on the support, we successfully fabricated the U-shaped anode-supportedHF-SOFC NiO-YSZ/YSZ/YSZ-LSM/LSM. By using of the YSZ-LSM composite cathodelayer and existing of the LSM cathode current collection layer, the cell manifests goodelectrochemical performance, the maximum power density is884mW cm-2and thepolarization resistance is0.36Ω cm~2at750oC. Moreover, the cell shows good thermalcycling performance and stability, undergoing65thermal cycles; after the65thermal cycles,the cell works for additional100h. The total stabilized operation time of the cell is425h.