【作者】 王强；

【导师】 由宏新；

【作者基本信息】 大连理工大学 ， 安全科学与工程， 2021， 硕士

【摘要】 固体氧化物燃料电池（Solid Oxide Fuel Cell,SOFC）是新能源领域具有相当应用前景的发电技术,实际运行中电功率密度偏低。本文主要通过探索新的电池制作工艺和材料制备方法来制备更高功率密度的SOFC,从界面优化和阳极微观改性两个微尺度来提升电池的电化学性能。实验采用了3D复刻法和压印法两种工艺制备具有非平整电极-电解质界面的燃料电池。结果发现:3D复刻法对打印设备要求苛刻,制备的电解质基片具有较大的热应力;压印法流程简单,借助孔网、以阶段式加压的工艺,成功制备得到微观表面形态平整、网格密度不同的YSZ电解质基片。电解质基片经涂覆Ni O-YSZ阳极和LSM-YSZ阴极,成功得到具有20目、30目、40目网格界面的单电池。电化学测试结果表明网格界面单电池性能随网格密度增大而增加,40目网格单电池的最大功率密度相比平整单电池在900℃、800℃下提升幅度约40%,尤其是甲烷燃料性能随网格增加更明显。对单电池阳极-电解质界面及阳极表面微观形貌分析,发现高密度网格单电池增加了阳极和电解质的接触面,同时电解质厚度减薄的面积也增大了,阳极印痕处表面呈现分布均匀的孔洞结构。这些微观微米级结构的变化增加了电化学的三相界面密度,减小了电解质的欧姆极化和阳极的浓差极化,提升了电池的电化学性能。微米级微观尺度的界面优化可以提高电池的输出性能。采用机械混合法、GNP法和模板浸渍法制备Ni基和Ni-Fe双金属阳极,并分析材料物相、相貌。发现GNP法制备了纳米级团簇的催化剂颗粒,硬模板法制备了高纯度的萤石结构YSZ丝状纤维,浸渍硝酸盐溶液、煅烧还原得到了纳米催化颗粒均匀附着在电解质骨架的复合阳极。各阳极与40目网格电解质制备的阳极半电池经孔隙分析发现,机械法制备的阳极材料具有有限的孔隙率和比表面积,结合GNP法制备的阳极粒径减小,其比表面积得以增加,硬模板法中YSZ复刻了活性炭纤维毡结构中的高比表面积,其浸渍得到的阳极具有高孔隙、高比表的特点。电化学性能测试发现Ni_0.75Fe_0.25O_x包覆YSZ阳极在900℃下H₂、CH₄的最大功率密度分别为359 m W/cm²和389 m W/cm²,在800℃下分别为263 m W/cm²和163 m W/cm²;与传统Ni O-YSZ阳极相比,同温度下H₂发电性能超过73%、CH₄超过68%;该阳极微观形貌质量较高,催化剂联结成多微孔网状结构,提供了更多的反应位点,增大了反应的三相界面。充分表明,硬模板法结合浸渍法可以制备高性能纳米级SOFC阳极。更多还原

【Abstract】 Solid Oxide Fuel Cell（SOFC） is a kind of power generation technology in new energy field with great application prospect,but its electric power densities were slightly lower in actual operation.In this paper,SOFC with higher power density was prepared by exploring the new production process and material fabrication method,and the interface optimization and the anode micro-modification were used to improve the electrochemical performance of SOFC.In the experiment,the 3D reprinting method and the pressed imprinting method were used to prepare SOFC with non-planer electrode-electrolyte interface.The results showed that the 3D reprinting method had rigorous requirements to 3D printing equipment,and the prepared electrolyte substrates using this method had the large thermal stress in operating temperature.The the pressed imprinting method was the simple process,which used the pore network as medium and used the staged pressurization and re-pressurization.The obtained yttria-stabilized zirconia（YSZ）electrolyte substrates had the smooth microcosmic surfaces and different mesh densities.The complete SOFC with 20-mesh,30-mesh and 40-mesh interface were fabricated after coating the Ni O-YSZ anode and the La_0.85Sr_0.15Mn O₃（LSM）cathode.Through the electrochemical test,it was found that the performance of SOFC increased with the addition of grid densities.The maximum power densities of the 40-mesh unit cell were about 40%higher than those of non-mesh cell at 800°C and 900°C,especially the increase of the performance was more obvious in CH₄.The anode-electrolyte interface and anode surface micromorphologies were analyzed by SEM.It was found that the high-density mesh SOFC increased the contact surface between anode and electrolyte,meanwhile the area of thin electrolyte layer was added and the anode surface at the impress place presented the uniform distribution of pore structure.The changes of microstructure increased the densities of three-phase boundery（TPB）and reduced the electrolyte ohmic polarization and the anode concentration polarization,which improved the electrochemical performance of SOFC.It was shown that the interface optimization can improve the output performance of the unit cell.The Ni-based anodes and Ni/Fe-based anodes were prepared by different methods by mechanical mixing,GNP and template impregnation methods.And all anodes were analyzed the phase and microstructure by XRD and SEM.It was found that glycine-nitrate process（GNP）was beneficial to prepare the catalyst particles clustered with nanoparticles.High purity YSZ filamentous fibers with fluorite structure were prepared by hard template method.After impregnation with nitrate solution,calcination and reduction,the catalytic nanoparticles were uniformly attached to the anode framework.The half unit cell prepared by differert anodes with 40-mesh electrolyte substrate were analyzed the porosities and specific areas.It was found that the anode materials prepared by mechanical method had limited porosities and limited specific surface areas.And the anode prepared by GNP method had the increased specific surface areas due to the decrease of particles’size.The YSZ with high specific surface area reproduced the strutureof activated carbon fiber by hard template method,hence the anodes obtained by impregnation had the characteristics of high porosities and high specific surface areas.The electrochemical performance test showed that the maximum power densities of the Ni_0.75Fe_0.25O_x coated YSZ anode were 359 m W/cm² and 389 m W/cm² at 900°C using H₂ and CH₄as fuel,and the values were 263 m W/cm² and 163 m W/cm² at 800°C respectively.The cell performance of that anode were 73%and 68%higher than the traditional Ni O-YSZ anode.It was also found that the Ni_0.75Fe_0.25O_x coated YSZ anode with high quality micromorphology contained multi-pore network structure formed by catalytic nanoparticles,which provided more reaction sites and increased more TPB areas,compared with the Ni O-YSZ anode prepared by mechanical method.It showed that the nanometer anode of SOFC with high-performance can be prepared by hard template method and impregnation method.更多还原