电沉积法低温制备纳米结构固体氧化物燃料电池高性能薄膜及电沉积机理研究

Lowering Solid Oxide Fuel Cell(SOFC) fabricating cost and improving its performance are the keys in its commerial application.In this project, a puls depositing GDC dense electrolyte films technique will be developed. The hdrogen and hyoxide bond will be deleted by puls deposition to prevent the cracks which occurs in the constant potential method. Also the effect of processing parameter on the structure and the conductivity of the deposited GDC films will be systemically studied. With the tests of electrochemical impedance spectroscopy,cyclic voltage and electrochemical quartz-crystal microbalance, rotating disc electrode together with X-ray surface microanalysis,by comparing the depositing behaviors between the CeO2, Gd2O3 and GDC, the depositing mechanism will be studied. The conductive Fe layer will be electroless deposited on the GDC electrolyte surface, then the nano GDC-LSCF composite cathodes will be developed by hydrogen tempate，with GDC as the basic matter and LSCF as the suspended particulates.The composite cathodes will improve its performance by expanding the reactive area.According the two steps absorption model, the relation between the LSCF content in the deposited layer, the LSCF content in the solution and the overpotential will be developed. The rate controlling step will be confirmed.Finally the depositing mechanism will be verified. A new method of fabricating SOFC component with high performance and low cost will be developed in this project. Especially the study will provide the base for low-cost fabrication SOFC nanostructured membranes. SOFC component with high performance and low cost will be developed in this project.

提高性能降低成本是SOFC商业化发展的关键。本项目拟采用脉冲电沉积技术，消除恒电位法中氢键和氢氧键吸附导致的薄膜开裂，制备致密的GDC电解质，研究制备条件对GDC的结构和电导率之间的影响规律，并借助EIS、CV-EQCM、RDE、EDX等手段，对CeO2、Gd2O3和GDC薄膜的电沉积行为进行比较研究，阐明GDC薄膜的电沉积机理。通过化学沉积Fe使室温下不导电的GDC表面金属化，然后以氢气泡为模板，GDC为基质，纳米LSCF为微粒，采用复合电沉积法快捷地制备三维多孔GDC-LSCF复合阴极，扩大三相反应界面，提高电催化活性。并根据两步吸附模型，建立沉积层中LSCF含量、溶液中LSCF浓度以及阴极过电位之间的方程式，确定共沉积过程的速度控制步骤，阐明GDC-LSCF的复合电沉积机理。本项目既开辟了低成本制备高性能SOFC的新方法，又为SOFC纳米薄膜的低成本可控制备提供了理论依据和实验基础。

提高性能降低成本是SOFC商业化发展的关键，其瓶颈主要在电解质。电沉积法可以低温制备纳米结构氧化物薄膜。本项目采用脉冲电沉积法，利用脉冲电源阴阳极的不断变换，有效的消除了氢键和氢氧键在沉积基体表面的结合，抑制了恒电位法制备时所产生的裂纹，得到了较为致密的GDC薄膜。采用CV、EQCM、RDE、EDX、SEM等研究了GDC的电沉积机理，发现GDC薄膜是在氧饱和的Gd3+、Ce4+溶液中由阴极极化生成，其生成机理为：导电基体上可溶性前驱体的还原导致基体表面OH-的生成，然后这些OH-同溶液中存在的金属阳离子反应，在电极表面生成氢氧化物最后脱水转化为氧化物薄膜。进一步热处理可以将Ce2O3氧化为CeO2，并且将Gd3+掺杂进CeO2晶格中，生成GDC，还可以使GDC致密化，得到更为完美的结构和形貌。热处理温度和Gd的掺杂影响了沉积层晶粒的尺寸，进而影响了微裂纹的生成。Ce0.8Gd0.2O2-δ和Ce0.92Gd0.08O2-δ薄膜的平均粒径在28nm左右时无裂纹产生，得到了100nm厚的致密GDC薄膜。为低温制备高性能固体氧化物燃料薄膜提供了新的思路。根据项目计划书，圆满完成了研究内容。并利用多种方法，制备了MoS2-r-GO、Ag-MoS2、CuCrO2/MWCNTs等多种结构独特的锂离子电池负极材料，取得了一系列优异的储锂性能。