NiO-YSZ-石墨水系浆料的研制及其在注浆成型制备固体氧化物燃料电池中的应用

Ni-YSZ(钇稳定氧化锆)金属陶瓷普遍被用作固体氧化物燃料电池(SOFC)的阳极材料,其氧化物浆料的性质对湿法制备的SOFC的性能具有重要影响.通过zeta电位分析,研究了NiO-YSZ双分散相水系浆料的稳定性.对六种分散剂作用于NiO、YSZ表面的zeta电位进行研究,发现采用的阴离子分散剂和两性分散剂使NiO和YSZ在水中带有相反电荷而引起迅速絮凝;采用阳离子分散剂聚二烯二甲基氯化铵(PDAC)时,NiO和YSZ因带有正电荷相互排斥而稳定分散于水中,在此基础上,加入作为SOFC阳极造孔剂的石墨,采用聚乙烯吡咯烷酮(PVP)作为石墨的分散剂,制备出了NiO-YSZ-石墨的稳定水系浆料.采用此浆料通过注浆成型制得阳极支撑管,进而组装成SOFC单电池.该单电池在800°C时最大功率密度达到509 mW·cm-2;扫描电镜(SEM)分析表明电极与电解质间接触良好,阳极孔洞分布均匀.     

复合阳极共烧制备致密La0.7Ca0.3Cr0.97O3-δ连接体薄膜的研究

固体氧化物燃料电池(SOFC)陶瓷连接材料的低成本薄膜化制备是现在公认的技术难题。为了改善传统NiO/YSZ阳极与LaCrO3基连接材料的共烧匹配性能,将化学性质稳定的Y0.7Ca0.3Cr0.9Zn0.1O3-δ(YCCZ)连接材料创造性地引入到NiO/YSZ阳极中,制备NiO/YSZ/YCCZ(6∶4∶2,m/m/m)三相复合阳极,并进行烧结特性、微观结构、电导率、热膨胀系数等系列性能的对比测试,结果表明NiO/YSZ/YCCZ新型复合阳极具有优良的综合性能。以NiO/YSZ/YCCZ为支撑体,采用浆料浸渍法制备湿膜,1 400℃空气条件下共烧,成功制备致密La0.7Ca0.3Cr0.97O3-δ连接体薄膜。     

中温固体氧化物燃料电池NiO/YSZ阳极的还原过程

以氢气程序升温还原(H2-TPR)为手段,研究了中温固体氧化物燃料电池烧结NiO/YSZ阳极的还原过程,并通过对电池开路电位和阻抗的原位监测考察了电池中阳极的还原过程.H2-TPR结果表明,阳极烧结温度升高,阳极中的NiO变得难以还原,但当温度提高到1 500℃时,NiO还原峰的峰温降低.阳极NiO含量越高,NiO越容易被还原.这是由于烧结过程中NiO颗粒长大和NiO/YSZ界面分离共同作用的结果.电池原位还原过程中开路电位的变化表明,具有高NiO含量的阳极还原较慢.这主要是由于高NiO含量的阳极具有较大的收缩率和大的NiO粒子,导致还原初期产生的大量H2O不能被及时排出,从而抑制了还原过程.电池还原过程中交流阻抗谱的变化表明,50%NiO/YSZ阳极具有最稳定的还原过程.30%和70%NiO/YSZ电池都有一个极化电阻逐渐增大的过程,前者的极化电阻在还原600 min后逐渐稳定,而后者并不能稳定.     

薄膜型中温固体氧化物燃料电池 (SOFC)研制及性能考察

用一种廉价的湿化学方法 ,在Ni_YSZ阳极基膜上制备出致密的YttriaStabilizedZirconia(YSZ)薄膜 .薄膜的厚度约为 10 μm ,致密均匀 ,无裂纹等缺陷 .以Ni_YSZ阳极基膜 ,YSZ薄膜和锶掺杂锰酸镧阴极 (LSM )组装的SOFC单电池 ,在 80 0℃下功率密度达 0 1W /cm2 .研究分析表明 ,YSZ薄膜的IR降 (包括电极 /YSZ薄膜的接触电阻 )较小 ,不是影响电池性能的主要因素 ,大的阳极过电位是影响电池性能的主要因素 .     

Ag-GDC复合电极的性能及其在直接碳SOFC中的应用

制备了Ag与Gd掺杂的氧化铈(GDC)复合的电极材料。采用氧化钇稳定的氧化锆(YSZ)为电解质,Ag-GDC为阴极和阳极,组装成固体氧化物燃料电池(SOFC),采用担载5%(质量分数)Fe的活性炭为SOFC的燃料,对此直接碳SOFC(DC-SOFC)的输出性能及阻抗谱进行测试,并与采用传统阴极(掺Sr的锰酸镧与YSZ的复合材料)的DC-SOFC性能进行了比较,发现Ag-GDC具有更好的性能。采用扫描电镜(SEM)对电池的微观结构进行了分析,并就其对电池性能的影响进行了分析。     

乙醇在Ni-ZnO-ZrO_2-YSZ阳极SOFC上的发电性能

为考察乙醇用于固体氧化物燃料电池的可行性,用柠檬酸溶胶-凝胶制备阳极催化材料Ni-ZnO-ZrO2,利用机械混合法制备Ni-ZnO-ZrO2-YSZ(Y2O3稳定的ZrO2)阳极。用涂覆法,在YSZ电解质上,制备了Ni-ZnO-ZrO2-YSZ/YSZ/LSM(La0.85Sr0.15MnO3)与Ni-YSZ/YSZ/LSM的单体电池。在不同蒸发器操作温度、电池操作温度和乙醇蒸气流量下,以乙醇为燃料进行发电实验,对两种阳极的电池发电性能进行比较。实验结束后,用SEM检测了两种电池阳极的表面。结果表明,Ni-ZnO-ZrO2-YSZ阳极SOFC的电池输出性能明显高于Ni-YSZ阳极,且Ni-ZnO-ZrO2-YSZ阳极具有较好的抗积炭能力。     

YSZ传导膜H_2S固体氧化物燃料电池

研究了Y2O3稳定的ZrO2(YSZ)氧离子传导膜H2S固体氧化物燃料电池性能。掺杂NiS、电解质、Ag粉和淀粉制备了双金属复合MoS2阳极催化剂,掺杂电解质、Ag粉和淀粉制备了复合NiO阴极催化剂,用扫描电镜对YSZ和膜电极组装(MEA)进行了表征,比较了不同电极催化剂的性能和极化过程,考察了不同温度对电池性能的影响。结果表明,双金属复合MoS2/NiS阳极催化剂在H2S环境下比Pt和单金属MoS2催化剂稳定,复合NiO阴极催化剂比Pt性能好,在电极催化剂中加入Ag可显著提高电极的导电性;与Pt电极相比,复合MoS2阳极和复合NiO阴极催化剂的过电位较小,阳极的极化比阴极侧小;温度升高,电池的电流密度与功率密度增加,电化学性能变好。在750℃、800℃、850℃和900℃及101.13 kPa时,结构为H2S、(复合MoS2阳极催化剂)/YSZ氧离子传导膜/(复合NiO阴极催化剂)、空气的燃料电池最大功率密度分别为30 mW/cm2、70 mW/cm2、155 mW/cm2及295 mW/cm2、最大电流密度分别为120 mA/cm2、240 mA/cm2、560 mA/cm2和890 mA/cm2。     

梯度Cu-CeO2-Ni-YSZ复合阳极直接甲烷SOFC的制备与性能

采用三层共压-共烧结法, 并涂覆La_0.8Sr_0.2MnO₃ (LSM)阴极, 制备了梯度Ni-YSZ阳极结构的固体氧化物燃料电池(SOFC)(大孔Ni-YSZ|微孔Ni-YSZ|YSZ|LSM) (YSZ: Y₂O₃稳定的ZrO₂; LSM: Sr 掺杂的LaMnO₃).通过浸渍法在大孔Ni-YSZ 基底中沉积占总重量约1%的Cu-CeO₂抗积碳催化剂, 形成梯度Cu-CeO₂-Ni-YSZ复合阳极. 分别以CH₄和H₂为燃料, 空气为氧化剂, 测定了构造的SOFC输出电性能和长期稳定性. 结果表明,三层共压-共烧结法制备的梯度阳极SOFC, 层间结合紧密无缺陷, 阳极梯度孔结构明显, YSZ膜致密无缺陷.在850℃下操作, 以梯度Ni-YSZ 阳极制备的SOFC, 燃料由H₂切换为甲烷时, 最大功率密度由284 mW·cm^-2下降到143 mW·cm^-2; 而以Cu-CeO₂-Ni-YSZ 复合阳极构造的SOFC出现相反趋势, H₂切换为甲烷后最大输出由176 mW·cm^-2增加到196 mW·cm^-2. 在250 mA·cm^-2负荷下, 梯度Ni-YSZ阳极支撑的直接甲烷SOFC仅稳定运转10 h 便出现明显衰减, 阳极中积碳严重; 但Cu-CeO₂-Ni-YSZ 复合阳极支撑SOFC连续运转50 h, 输出电压与输出功率密度基本不变, 电镜观察不到积碳.     

低温制备掺杂氧化锆/氧化铈电解质

固体氧化物燃料电池(SOFC)及其组元的低温制备有利于材料和电池性能的优化,降低制备成本.立方相的全致密氧化钇稳定氧化锆(YSZ)电解质是SOFC中最通用的电解质.传统的烧结工艺需要在1 400-1 450℃才能实现YSZ电解质的致密,而使用纳米粉体和三步烧结工艺可以在1 200-1 300℃得到致密电解质.氧化钪稳定...     

Cu-CeO2基阳极直接甲烷SOFC的制备及其性能

采用干压法制备了NiO-YSZ(氧化钇稳定氧化锆)/(ZrO2)0.89(Sc2O3)0.1(CeO2)0.01(10ScSZ-1CeO2)半电池, 经还原-酸溶法除去NiO制备了多孔YSZ负载致密10ScSZ-1CeO2双层结构, 通过浸渍法在多孔YSZ阳极基体中引入Ce、Cu的硝酸盐制备Cu-CeO2-YSZ复合阳极, 结合La0.6Sr0.4Co0.2Fe0.8O3-δ(LSCF)阴极构建了Cu-CeO2-YSZ/10ScSZ-1CeO2/LSCF单元电池. 通过X射线衍射(XRD)和场发射扫描电镜(FESEM)等手段对电池单元的物相、微观结构进行表征. 结果表明: 还原-酸溶法制备的YSZ/10ScSZ-1CeO2双层结构的YSZ基体具有孔隙率高(>64%)、孔洞连通性好的微观结构, 有助于采用浸渍法引入Ce、Cu硝酸盐; 10ScSZ-1CeO2电解质薄膜致密无缺陷, 厚约30 μm. 电性能测试表明所构建单元固体氧化物燃料电池(SOFC)具有良好的电性能输出, 在650 ℃以湿H2和CH4为燃料时的最大功率密度分别为0.29和0.09 W·cm-2; 在700 ℃以湿H2和CH4为燃料时的最大功率密度分别达到0.48 和0.21 W·cm-2. 优良的电性能主要归功于小的电解质内阻和阴极极化电阻以及良好的阳极微观结构.     

A novel multistep dip-coating method for the fabrication of anode-supported microtubular solid oxide fuel cells

A novel multistep dip-coating method was developed and successfully applied to the fabrication of anode-supported microtubular solid oxide fuel cells (SOFCs) using carbon rods as combustible cores. The fabricated microtubular SOFCs consisted of Ni-yttria-stabilized zirconia (YSZ), YSZ, strontium-doped lanthanum manganite (LSM)–YSZ, and LSM as the anode, electrolyte, cathode, and cathode current collector materials, respectively. To investigate the role of anode porosity on cell performance, two types of anode supports were prepared: one without a pore former and the other with a 10 wt.% graphite pore former. The microstructural features of the microtubular SOFCs were examined using scanning electron microscope images whereas the electrochemical performance was characterized by electrochemical impedance spectroscopy measurements as well as I–V characteristic curves. The results showed that the method used is a simple and low-cost alternative to conventional methods for the fabrication of microtubular SOFCs. We found that the anode porosity played an important role in improving the overall performance of the microtubular SOFC by reducing the concentration polarization.     

Formation of NiO/YSZ functional anode layers of solid oxide fuel cells by magnetron sputtering

The decrease in the polarization resistance of the anode of solid-oxide fuel cells (SOFCs) due to the formation of an additional NiO/(ZrO₂ + 10 mol % Y₂O₃) (YSZ) functional layer was studied. NiO/YSZ films with different NiO contents were deposited by reactive magnetron sputtering of Ni and Zr–Y targets. The elemental and phase composition of the films was adjusted by regulating oxygen flow rate during the sputtering. The resulting films were studied by scanning electron microscopy and X-ray diffractometry. Comparative tests of planar SOFCs with a NiO/YSZ anode support, NiO/YSZ functional nanostructured anode layer, YSZ electrolyte, and La_0.6Sr_0.4Co_0.2Fe_0.8O₃/Ce_0.9Gd_0.1O₂ (LSCF/CGO) cathode were performed. It was shown that the formation of a NiO/YSZ functional nanostructured anode leads to a 15–25% increase in the maximum power density of fuel cells in the working temperature range 500–800°C. The NiO/YSZ nanostructured anode layers lead not only to a reduction of the polarization resistance of the anode, but also to the formation of denser electrolyte films during subsequent magnetron sputtering of electrolyte.     

Fabrication and performance test of solid oxide fuel cells with screen-printed yttria-stabilized zirconia electrolyte membranes

Yttria-stabilized zirconia (YSZ) membranes were deposited onto porous NiO–YSZ anode supports by screen printing. Combined with La_0.7Sr_0.3MnO₃–YSZ composite cathode, the prepared anode-supported solid oxide fuel cells (SOFCs) were electrochemically tested. A typical SOFC with a 30-μm-thick YSZ electrolyte membrane gave the maximum power densities (MPDs) of 0.26, 0.53, 0.78, and 1.03 W/cm² at 650, 700, 800, and 850 °C, respectively, using hydrogen as fuel and stationary air as oxidant. Replacement of stationary air with pure oxygen flow exerted a significant positive effect on the MPDs of the cell. Using 100- and 200-ml/min oxygen as oxidants, the MPDs of the cell were enhanced 35.3% and 68.6%, respectively. Polarization analysis indicated that, at the MPD points, the electrode polarization resistances accounted for 80% of the cell total resistances.

     

Fabrication and performance test of solid oxide fuel cells with screen-printed yttria-stabilized zirconia electrolyte membranes

Yttria-stabilized zirconia (YSZ) membranes were deposited onto porous NiO?CYSZ anode supports by screen printing. Combined with La_0.7Sr_0.3MnO₃?CYSZ composite cathode, the prepared anode-supported solid oxide fuel cells (SOFCs) were electrochemically tested. A typical SOFC with a 30-??m-thick YSZ electrolyte membrane gave the maximum power densities (MPDs) of 0.26, 0.53, 0.78, and 1.03?W/cm² at 650, 700, 800, and 850?°C, respectively, using hydrogen as fuel and stationary air as oxidant. Replacement of stationary air with pure oxygen flow exerted a significant positive effect on the MPDs of the cell. Using 100- and 200-ml/min oxygen as oxidants, the MPDs of the cell were enhanced 35.3% and 68.6%, respectively. Polarization analysis indicated that, at the MPD points, the electrode polarization resistances accounted for 80% of the cell total resistances.     

Comparison of characteristics of solid oxide fuel cells with YSZ and CGO film solid electrolytes formed using magnetron sputtering technique

The work describes the methods of manufacturing single cells of solid oxide fuel cell (SOFC) with thin–film YSZ and CGO electrolytes and also with the bilayer YSZ/CGO electrolyte. Formation of YSZ and CGO films on the supporting NiO–YSZ anode of SOFC was carried out using the combined electron–ionic–plasma deposition technique. The microstructure and phase composition of the formed coatings are studied and also comparative analysis of electrochemical characteristics of single fuel cells with different electrolytes is performed. It is shown that the maximum power density of 1.35 W/cm² at the temperature of 800°C is obtained for the cell with bilayer YSZ/CGO electrolyte. However, the highest performance at lower working temperatures (650–700°C) is characteristic for the fuel cell with single–layer CGO electrolyte; its power density is 600–650 mW/cm².     

NiO晶粒尺寸对SOFC阳极电化学性能的影响

用溶胶凝胶法合成了具有高比表面积的纳米粒子NiO,用固相合成法制备了NiO-YSZ复合材料.阻抗谱测试表明,含纳米尺寸NiO的复合材料的极化电阻更小,电导率更高.以质量分数为55%的NiO-YSZ为阳极材料,并将其封接成单电池.结果表明,含纳米尺寸NiO的复合阳极制成的单电池,其输出功率更高,短路电流更大.通过减小NiO晶粒尺寸,可增大阳极三相反应界面长度,并获得性能优良的阳极材料.     

银基陶瓷复合电极的电性能及其在固体氧化物燃料电池中的应用

银基陶瓷复合电极可望在中低温固体氧化物燃料电池(SOFCs)、含碳燃料SOFCs和固体氧化物电解池(SOECs)中得到广泛应用。为优选出银基陶瓷复合电极的成分,本研究采用YSZ(钇稳定化氧化锆)电解质,先将Ag-YSZ和Ag-GDC(掺钆氧化铈)材料制备成对称电极,测试其在空气下的阻抗谱,由此判断其作为阴极的性能;发现在相同的Ag含量时, Ag-YSZ的阴极极化电阻普遍低于Ag-GDC;当Ag的质量分数为65%时, Ag-YSZ的极化电阻最低,而对于Ag-GDC, Ag的质量分数是70%。然后采用空气中极化电阻最低的Ag-YSZ和Ag-GDC作为电极制备了SOFC单电池,并采用加湿氢气燃料对电池的电化学性能进行了测试。根据电池的阻抗谱数据,将极化阻抗的数值减去上述阴极阻抗的数值可得到阳极阻抗值,其结果和电池的输出特性均表明, Ag-GDC作为阳极的性能优于Ag-YSZ,即在本实验条件下, Ag-YSZ更适合用作阴极,而Ag-GDC更适合用作阳极。本研究不仅提供了关于银基复合电极材料的有用数据,还提供了一种测试SOFC阳极极化电阻的方法。     

A verification of the reaction mechanism of direct carbon solid oxide fuel cells

Anode-supported tubular solid oxide fuel cells (SOFCs) with Cu–CeO₂–yttria-stabilized zirconia (YSZ) anode, YSZ electrolyte film, and silver cathode were fabricated. The cells were tested with 5 wt% Fe-loaded activated carbon and dry CO, respectively, and their performances were compared to verify the reaction mechanism of direct carbon SOFCs (DC-SOFCs). The corresponding current–voltage curves and impedance characteristics of the cells operating on these two different fuels were found to be almost the same at high temperatures, demonstrating the presumed mechanism that the anode reaction of a DC-SOFC is the electrochemical oxidation of CO, just as in a SOFC operated directly on CO. Some experimental evidences including the difference in open circuit voltage at different temperatures and the operating stability of the cells were analyzed in detail.     

Performance studies of electrolyte-supported solid oxide fuel cell with Ni–YSZ and Ni–TiO2–YSZ as anodes

Redox cycling of Ni-based anode induces cell degradation which limits the cell's lifetime during solid oxide fuel cell operation. In the present study, the redox testing of electrolyte-supported cells has been investigated with TiO₂-added NiO–YSZ anode matrix. Button cells were fabricated by die-pressing YSZ powder as electrolyte, and onto which NiO–YSZ or NiO–TiO₂–YSZ anode and LSM–YSZ composite cathode were painted. The electrochemical performance and stability have been evaluated by measuring current–voltage characteristics followed by impedance spectroscopy after each redox cycling. Anode matrices before and after cell operation have been characterized by X-ray diffraction (XRD), elemental dispersive X-ray (EDX), and scanning electron microscopy (SEM). During cell operation the peak power density decreases from 111 mW cm^?2 (239 mA cm^?2) to 84 mW cm^?2 (188 mA cm^?2) between 23 and 128 h with five redox cycles for cell having NiO–YSZ (40:60) anode. But for cell with NiO–TiO₂–YSZ (30:10:60), the anode peak power density was constant and stable around 85 mW cm^?2 (194 mA cm^?2) throughout the cell run of 130 h and five redox cycles. No loss in the open circuit voltage was observed. SEM and XRD studies of NiO–TiO₂–YSZ (30:10:60) anodes revealed formation of ZrTiO₄, which may be responsible for inhibition of Ni coarsening leading to stable cell performance.