微管式固体氧化物燃料电池阳极结构设计与性能研究

It is urgent need to develop high-performance microtubular solid oxide fuel cells (SOFCs) technology for efficient electric power generation. The project is proposed to design and controlledly fabricate ideal dual-layer anode with long straight macro-pores layer and thin sponge-like pore layer for the advanced, high-performance microtubular SOFCs via the phase inversion spinning method. In this proposal, the relationship between the parameters of the phase inversion spinning process and the anode microstructure revolution will be studied by directly characterizing the parameters of the anode microstructure, including porosity, tortuosity factor, etc., via the three-dimensional reconstruction technique using the X-ray computed tomography (XCT), and the effect of the anode microstructure on the cell performance of anode-supported microtubular SOFCs, including the open circuit voltage, peak power density and polarization resistance, will be systematically investigated. The proposal is also expected to analyze the effect of the anode microstructure on the rate-limiting step in the microtubular SOFCs during the electrochemical reaction process via the distribution function of relaxation times method (DRT), and to build the correlation between the anode microstructure, operating conditions and the cell performance, and then to further explain the anode reaction mechanism, which will offer an effect way to design and controlledly prepare the advanced anode for high-performance microtubular SOFCs.

本项目结合发展新型高性能微管式固体氧化物燃料电池（SOFC）技术的迫切需要，针对高性能SOFC对阳极结构的要求，采用相转化纺丝技术设计并可控制备适用于高性能微管式SOFC的理想结构阳极——长直孔层/薄海绵状孔层双层结构阳极。本项目还将采用X-射线体层成像仪（XCT）-三维重整技术真实还原微管式SOFC的空间结构（孔隙率、曲折因子等），系统研究阳极结构参数与相转化纺丝技术参数之间的演变规律，探究阳极结构对阳极支撑微管式SOFC开路电压、最大功率密度、极化电阻等电化学性能的影响；同时引入弛豫时间分布法（DRT）方法，解析阳极结构与微管式SOFC电极反应速控步骤之间的关系，建立阳极结构、工作条件、电池电化学性能之间的规律，解释微管式SOFC的电极反应机理，并以此为依据设计并可控制备高性能微管式SOFC阳极。

本项目结合发展新型高性能微管式固体氧化物燃料电池（SOFC）技术的迫切需要，采用相转化纺丝技术设计并可控制备了适用于高性能微管式SOFC的理想结构阳极（氢气极）——长直孔层/薄海绵状孔层双层结构阳极。采用扫描电镜和X-射线体层成像仪-三维重整技术研究了微管式SOFC阳极的空间结构参数（孔隙率、曲折因子等），确立了阳极结构参数与相转化纺丝技术参数之间的演变规律，探究了阳极结构对阳极支撑微管式SOFC开路电压、最大输出功率密度、极化电阻等电化学性能的影响；同时引入弛豫时间分布法（DRT）方法解析了阳极结构与微管式SOFC电极反应速控步骤之间的关系，建立了阳极结构、工作条件、电池电化学性能之间的规律，解释了微管式SOFC的电极反应机理。研究表明N-甲基-2-吡咯烷酮是一种理想的相转化溶剂，通过设计和可控制备长直孔层/薄海绵状孔层双层结构阳极，800oC，湿润氢气为燃料时，阳极支撑微管式SOFC的最大输出功率密度可以由482 mWcm-2增加到1209 mWcm-2，电池的欧姆电阻、总电阻和电极极化电阻分别由0.178Ωcm2、0.627Ωcm2和0.449Ωcm2降低为0.140Ωcm2、0.255Ωcm2和0.115Ωcm2。通过对电化学阻抗进行分析发现欧姆电阻的降低源于阳极/电解质接触电阻的降低，而电极极化电阻的优化可能的原因是阳极功能层的引入将显著增加阳极/电解质界面处的三相线密度，有效降低电极的活化极化电阻，进而显著提高电池的电化学性能。本项目的研究工作将为设计并可控制备高性能微管式SOFC提供实验和理论基础，有望促进微管式SOFC技术的商业化应用。