中温固体氧化物燃料电池新型复合阴极材料的制备及电化学性能

发布时间：2018-03-20 01:22

本文选题：固体氧化物燃料电池　切入点：离子浸渍法　出处：《合肥工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：固体氧化物燃料电池(Solid Oxide Fuel Cell,SOFC)因具有能量转换效率高、燃料可选范围广,环境友好等优点而受到广泛关注。实现SOFC的产业化发展,关键是降低其工作温度和成本。但是,随着温度的降低,阴极的极化电阻增加,导致电池性能降低。因此,高性能阴极材料的研发是当前SOFC领域研究的热点之一。在阴极材料中添加适量的催化材料或者电解质材料制备复合阴极,可以有效提高阴极表面的氧化还原反应(ORR)过程,从而降低阴极的极化电阻。离子浸渍法是一种新颖的SOFC多孔复合电极制备技术。该技术通常先将阴极制成多孔骨架,然后将含电极活性材料的液相在毛细管力的驱动下渗入此多孔骨架中,前驱体经低温热分解生成相应的氧化物,从而实现电极活性材料相和阴极骨架的复合。该工艺制得的电极催化活性高、低温性能好,是提高SOFC性能,降低其工作温度的一个重要途径。本论文第二章通过水热法在多孔La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)-Sm_(0.2)Ce_(0.8)O_(1.9)(LSCF-SDC)复合阴极表面负载Co_3O_4催化剂,并对改性前后样品的物相结构,显微组织,电化学性能及其单电池的功率密度进行测试。实验结果表明,对LSCF-SDC阴极浸渍Co(NO3)2·6H2O溶液,经700°C焙烧后,可在复合阴极表面形成针状Co_3O_4。浸渍处理使700°C下LSCF-SDC复合阴极的界面阻抗由0.49Ω·cm~2降低至0.19Ω·cm~2,阴极的氧还原反应活化能由1.52 eV降低至1.03 eV。此外,Co_3O_4浸渍阴极使700°C下单电池的功率密度由185 mW·cm-2提高至259 mW·cm-2。初步结果表明,通过Co_3O_4浸渍改性,可有效提高LSCF-SDC复合阴极和由其构成的单电池的性能。本论文第三章通过离子浸渍法对Mn_(1.5)Co_(1.5)O_4(MCO)阴极骨架浸渍SDC纳米颗粒,制备新型MCO-SDC复合阴极材料。对复合阴极的化学稳定性、显微组织、电化学性能及其单电池的功率密度等进行分析,并与由机械混合法制备的MCO-SDC复合阴极进行比较。实验结果表明,MCO与SDC的复合样品在1200°C烧结2 h后没有发生化学反应,说明MCO与SDC在SOFC的工作温度范围内具有良好的化学稳定性。对多孔MCO阴极骨架浸渍含Sm和Ce的硝酸盐溶液,在700°C焙烧2 h,后,可在阴极表面形成一层SDC纳米颗粒。与机械混合法制备的MCO-SDC复合阴极相比,采用SDC浸渍处理所制备的MCO-SDC复合阴极在700°C下的界面阻抗从5.23Ω·cm-2降低至1.63Ω·cm-2。说明以纳米颗粒形式附着在MCO阴极表面的SDC,使阴极的三相反应区由阴极/电解质的界面延伸至阴极内部,促进了阴极表面的氧还原反应过程。此外,浸渍SDC处理使SOFC单电池在700°C下的功率密度由252 mW·cm-2提高至366 mW·cm-2。本论文第四章通过柠檬酸法制备出了Sr2Fe1.5-xCuxMo0.5O6-δ(x=0,0.05,0.1,0.2,0.3)(SFCxM)粉体,并通过压制烧结获得烧结体,系统考察了Cu元素掺杂量对SFM材料的物相,电导率,热膨胀系数及电化学性能等的影响。XRD表明,随着Cu元素掺杂量的增加,所有SFCxM粉体均展现出立方型钙钛矿结构,没有杂相出现,并且材料的晶胞逐渐膨胀。热膨胀性能测试表明,随着Cu元素掺杂量的增加,SFCxM材料的热膨胀系数逐渐增加,为14.5~(-1)6.1 K~(-1)。电导率测试结果表明,随着Cu元素掺杂量的增加,SFCxM材料的电导率先增加后减小,当掺杂量x=0.1时,SFC0.1M材料在450°C下的电导率可以达到49.3 S·cm~(-1),是未掺杂Cu的SFM材料电导率的2.5倍。此外,SFC0.1M阴极材料在800°C下具有最低的界面阻抗,达0.26Ω·cm~2,仅为SFM材料界面阻抗的40%。当SFC0.1M与SDC的质量百分比为60:40时,复合阴极的界面阻抗进一步降低至0.15Ω·cm~2。
[Abstract]:Solid oxide fuel cell (Solid Oxide Fuel Cell, SOFC) because of its high energy conversion efficiency, wide range of optional fuel, environmental friendliness and widespread concern. Realize the development of the SOFC industry, the key is to reduce the working temperature and cost. However, with the decrease of temperature, cathodic polarization resistance increases, causing the battery the performance is reduced. Therefore, the development of high performance cathode material is one of the research hotspots in the field of SOFC. Adding appropriate electrolyte materials or catalytic materials for preparing composite cathode on the cathode material, can effectively improve the cathode surface redox reaction (ORR) process, so as to reduce the polarization resistance of the cathode ion impregnation method is. Novel porous SOFC composite electrode preparation technology. The technology is usually the first cathode made of porous skeleton, and then with the electrode active material in liquid phase infiltration driven by capillary force The porous skeleton, the precursor by low temperature decomposition of the corresponding oxide, so as to realize the composite electrode active material and cathode skeleton. The catalytic activity of electrode prepared by this process is high, low temperature performance is good, is to improve the performance of SOFC, an important way to reduce the working temperature of the size. The second chapter of this thesis by hydrothermal in porous La_ (0.6) Sr_ (0.4) Co_ (0.2) Fe_ (0.8) O_ (3- 8) -Sm_ (0.2) Ce_ (0.8) O_ (1.9) (LSCF-SDC) composite cathode surface load Co_3O_4 catalyst, the microstructure of samples before and after the change of phase structure, power density, electrochemical performance and single cell test. The experimental results show that the LSCF-SDC impregnated Co (NO3) cathode 2 6H2O solution, after calcined at 700 ~ C, can be formed on the surface of the acicular Co_3O_4. composite cathode impregnated the interface resistance of LSCF-SDC composite cathodes 700 DEG C by 0.49. Anti cm~2 decreased to 0.19. Cm~2., cathode The oxygen reduction reaction activation energy decreased from 1.52 eV to 1.03 eV. in addition, Co_3O_4 to 700 DEG C impregnated cathode power density of single cell by 185 mW - cm-2 increased to 259 mW cm-2. preliminary results show that Co_3O_4 modified by impregnation, can effectively improve the performance of LSCF-SDC composite cathode and single cell formed by this. The third chapter by ion impregnation method on Mn_ (1.5) Co_ (1.5) O_4 (MCO) cathode skeleton impregnated with SDC nanoparticles, preparation of novel MCO-SDC composite cathode materials. The chemical stability of composite cathode microstructure analysis and electrochemical performance of single cell power density, and compared with MCO-SDC composite cathode is prepared by mechanical mixing method. The experimental results show that the composite samples of MCO and SDC at 1200 DEG C sintering after 2 h without chemical reaction, MCO and SDC in the temperature range of SOFC has good chemical stability. Nitrate solution of porous MCO cathode skeleton impregnated containing Sm and Ce, at 700 C after 2 h roasting, one layer of SDC nanoparticles formed on the cathode surface. Compared with MCO-SDC composite cathode prepared by mechanical mixing method, the interface impedance by SDC impregnation for MCO-SDC composite cathode prepared at 700 ~ C from 5.23. Cm-2 decreased to 1.63. Cm-2. shows in the form of nanoparticles attached on the surface of SDC MCO cathode, the three-phase reaction zone of the cathode by extending to the interface inside the cathode cathode / electrolyte, promote the reaction process of the cathode surface oxygen reduction. In addition, dipping at SDC SOFC battery power density under the temperature of 700 C by 252 mW - cm-2 - cm-2. mW is increased to 366. The fourth chapter of this thesis by citric acid was prepared by Sr2Fe1.5-xCuxMo0.5O6- 8 (x=0,0.05,0.1,0.2,0.3) (SFCxM) powder, and sintered by pressing and sintering system, the effects of Cu element doping The amount of SFM mixed material phase, conductivity,.XRD coefficient and the electrochemical performance of thermal expansion shows that with the increase of Cu doping amount, all SFCxM powders exhibit a cubic perovskite structure without impurity phase appeared, and gradually expanded. The cell material thermal expansion performance tests show that with the increase of Cu doping amount, the thermal expansion coefficient of SFCxM gradually increased, 14.5~ (-1) 6.1 K~ (-1). The conductivity test results show that with the increase of Cu doping amount, the conductivity of SFCxM material increased first and then decreased, when the doping amount of x= 0.1, the electrical conductivity of SFC0.1M material under the temperature of 450 C can be up to 49.3 S - cm~ (-1), SFM is not the conductivity of doped Cu 2.5 times. In addition, SFC0.1M cathode material has the lowest interfacial impedance under the temperature of 800 C was 0.26. Cm~2, only the interface impedance of SFM material 40%. when the mass percentage of SDC was 60 and SFC0.1M At 40, the interface impedance of the composite cathode is further reduced to 0.15 Omega cm~2..

【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM911.4

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