固體氧化物燃料電池(solid oxide fuel cell,SOFC)是將化學能直接轉化成電能的高效綠色能源技術。將SOFC工作溫度由1000℃高溫降低至500-750℃中溫范圍是目前該領域的重要研究方向。工作溫度的降低有利于減小SOFC的制備和運行成本,提高結構穩(wěn)定性以及延遲使用壽命,但是同時也能夠導致陰極、電解質、陽極和其他元件的性能下降。特別是,由于陰極氧還原反應(oxygen reduction reaction,ORR)活化能大,導致陰極極化阻抗隨溫度降低顯著增大,從而限制了中溫SOFC的輸出功率。鈷基鈣鈦礦結構氧化物是重要的中溫SOFC陰極候選材料。它們具有高電子-離子混合電導率和ORR催化活性,但是也往往具有大的熱膨脹系數(thermal expansion coefficient,TEC),與常用電解質材料 Gd0.1Ce0.9O1.95(GDC)、Sm0.2Ce0.8O1.9(SDC)和La0.9Sr0.1Ga0.8Mg0.2O2.85(LSGM)等的TEC值不匹配,容易導致在高溫燒結或運行過程中SOFC結構的開裂,進而引起SOFC性能的惡化。而且,該類材料在相對較...

【文章頁數】：132 頁

【學位級別】：博士

【文章目錄】：
Abstract
摘要
Table of Major Symbols
1 Introduction
    1.1 Fuel Cells
    1.2 Solid Oxide Fuel Cell
        1.2.1 The Principal and Operation
        1.2.2 Efficiency
    1.3 Components of SOFC
        1.3.1 Anode
        1.3.2 Electrolyte
        1.3.3 Cathode
    1.4 SOFC Cell Designs
    1.5 Mixed Ionic Electronic Conductor and Its Oxygen Reduction Mechanism
        1.5.1 ABO₃ Perovskite
        1.5.2 Layered Perovskites LnBaCo₂O6-δ

    1.6 Motivation and Objective of this Thesis
2 Experimental Methods
    2.1 Synthesis of Cathode and Electrolyte Powders
        2.1.1 Sol-Gel Method for Synthesis of Cathode Powder
        2.1.2 Solution Combustion Process for Synthesis of Electrolyte
    2.2 Fabrication of Electrolyte Pellet
    2.3 Fabrication of Cathode Layers
    2.4 Characterization Techniques
        2.4.1 X-Rays Diffraction (XRD)
        2.4.2 Thermal Expansion Coefficient (TEC)
        2.4.3 Scanning Electron Microscopy (SEM)
        2.4.4 AC Impedance Spectroscopy
3 Composite cathodes of (LaBa)_0.45CoO_3-δ-SDC
    3.1 Introduction
    3.2 Experimental Details
        3.2.1 Powder Synthesis and Cell Fabrication
        3.2.2 Characterizations
    3.3 Results and Discussion
        3.3.1 Phase Structures
        3.3.2 Thermal Expansion Behavior
        3.3.3 Electrical Conductivities
        3.3.4 Microstructure of the Cathodes
        3.3.5 Electrochemical Performance
        3.3.6 Single Cell Performance
    3.4 Summary
4 Performance Comparison Between PrBa_0.92Co₂O_6-δ-SDC Composite CathodesSynthesized with Different Methods
    4.1 Introduction
    4.2 Experimental Details
        4.2.1 Sample Preparation
        4.2.2 Characterizations
    4.3 Results and Discussion
        4.3.1 Phases and Microstructures of the Cathodes
        4.3.2 Electrochemical Performance
        4.3.3 Single Cell Performance
    4.4 Summary
5 Effects of SDC Content on Performance of Composite Cathode Materials ofPrBao.92Co₂O_6-δ-SDC
    5.1 Introduction
    5.2 Experimental Details
        5.2.1 Powder Synthesis
        5.2.2 Characterizations
    5.3 Results and Discussion
        5.3.1 Phase Structures of the Composites
        5.3.2 Thermal Expansion Behavior
        5.3.3 Electrical Conductivities
        5.3.4 Microstructures of the Cathodes
        5.3.5 Electrochemical Performance of the Cathodes
        5.3.6 Reaction Mechanism of the Cathodes
    5.4 Summary
6 Composite Cathodes of Pr_0.95BaCo₂O_6-δ-SDC
    6.1 Introduction
    6.2 Experimental Details
        6.2.1 Sample Preparation and Characterizations
    6.3 Results and Discussion
        6.3.1 Phase Structure
        6.3.2 Thermal Expansion Behavior
        6.3.3 Microstructures of the Cathodes
        6.3.4 Electrical Conductivities
        6.3.5 Electrochemical Performance of the Cathodes
        6.3.6 Single Cell Performance
    6.4 Summary
7 Conclusions and Outlook
    7.1 Conclusions
    7.2 總結
    7.3 Outlook
    7.4 Innovative Points
    7.5 創(chuàng)新點
References
Research Projects and Publications during PhD Period
Acknowledgement
Curriculum Vitae



本文編號：4016382

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