固体氧化物燃料电池电解质材料的研究进展(英文)

固体氧化物燃料电池(solid oxide fuel cells,SOFCs)因具有能量转换率高,燃料适应性强,环境友好和操作方便等优点,受到了人们的普遍关注.发展中低温SOFCs是其商业化必然趋势.电解质材料是SOFCs的关键材料.对用于中低温SOFCs电解质材料的研究现状和进展进行了论述,并着重介绍了近年来受人们广泛关注的磷灰石型电解质材料.阐述了SOFCs电解质材料的研究趋势.     

Structural Characterization of Lanthanum Chromite Perovskite Coating Deposited by Magnetron Sputtering on an Iron-Based Chromium-Containing Alloy as a Promising Interconnect Material for SOFCs

Chromium-containing stainless steel (SS) is a prospective material for use as an interconnect in solid oxide fuel cells (SOFCs). However, during operations at high temperatures, the growth of oxide scales causes the performance of the interconnect and SOFC as a whole to deteriorate. The coating of SS 446 with a conducting perovskite is a potential method of slowing the growth of oxide scale and, therefore, improving overall SOFC performance. In the present research, the structural characterization of a pure LaCrO₃ thin film on the SS 446 substrates has been performed as a model material that can be used as a barrier coating for the metallic interconnect. The deposition of an amorphous La-Cr-O thin film on SS 446 was performed using radio-frequency (rf) magnetron sputtering. The deposited amorphous film was annealed in air to form the desired perovskite phase. The film underwent an amorphous to LaCrO₄ phase transition during annealing at 500°C with further transformation to LaCrO₃ orthorhombic phase during annealing at 700°C. A self-organized dendritic structure was reported as a result of the perovskite-phase formation. Although formation of various oxides, such as Fe₂O₃ and Fe₃O₄, was observed during the annealing of uncoated SS 446 in air, the coating of SS 446 surface with LaCrO₃ film prevented formation of various oxide phases at the interconnect surface. The structural characterization of the films and SS 446 surfaces was accomplished using scanning electron microscopy with energy-dispersive X-ray analysis, X-ray diffractometry, micro-Raman spectroscopy, and nanoindentation.     

Catalytic and Electrochemical Properties of Doped Lanthanum Chromites as New Anode Materials for Solid Oxide Fuel Cells

Defective perovskites contained in the general formula La(Sr)Cr(Ru,Mn)O_3–δ are successfully synthesized by spray pyrolysis. Powders of high phase purity are obtained after annealing, and they are used to prepare homogeneous films by spray printing. From a catalytic point of view for the methane steam reforming, these powdered perovskites do not generate a carbon deposit. Catalytic results, focused on doped ruthenium perovskites, confirm that the insertion of ruthenium in the structure of the lanthanum chromite presents a real benefit for the methane steam reforming. The electrochemical properties of La(Sr)CrO_3–δ, either pure and doped with manganese, show that the perovskite films can be potential electrodes, depending on their doping, for hydrogen anodic oxidation in solid oxide fuel cells.     

Control of the Thermal Expansion of Strontium-Doped Lanthanum Chromite Perovskites by B-site Doping for High-Temperature Solid Oxide Fuel Cell Separators

The thermal expansion of La_0.9Sr_0.1Cr_{1- x} M _x O₃(M = Mg, Al, Ti, Mn, Fe, Co, Ni; 0 ≤ x ≤ 0.1) perovskites has been studied in oxidizing and reducing atmospheres in the temperature range from 50° to 1000°C. Cobalt doping of La_0.9Sr_0.1CrO₃was an effective way of increasing the average linear thermal expansion coefficient (TEC), whereas titanium doping showed a negative effect. No effect on the TECs was observed for the B-site dopants in perovskites with the remaining dopants. Linear thermal expansion behavior was observed in the La_0.9Sr_0.1Cr_{1- x} M _x O₃ perovskites with doping of ≥1 mol% aluminum or 10 mol% cobalt. TECs of La_0.9Sr_0.1Cr_0.96Co_0.02Al_0.02O₃ were 10.5 × 10⁻⁶/°C in air, 10.7 × 10⁻⁶/°C under He–H₂ atmosphere (oxygen partial pressure of 4 × 10⁻¹⁵ atm at 1000°C), and 11.8 × 10⁻⁶/°C in H₂ atmosphere.     

The difference of PMMA-brush-modification on the oxygen permeable perovskite-type oxides by consisting elements

Oxygen permeation of perovskite-type ceramics consists of three elementary processes: oxygen absorption, bulk oxygen diffusion, and oxygen desorption. In most cases, the rate-determining step is the oxygen diffusion step, and the use of thin films improves the oxygen permeation rate of perovskite-type ceramics. Polymer-brush-modification is a useful technique to produce thin films. Grafted PMMA-brushes exhibit a screening effect for attractive interactions between core ceramic particles, thereby inducing repulsive forces on them. This results in the formation of a densely packed ordered array. Modification of the polymerization-initiator and polymer-brushes should affect the oxygen permeation properties of the ceramic particles, especially surface oxygen adsorption and desorption. In this paper, it is demonstrated that these modifications change the cation chemical states and lower the oxygen desorption rate, while increasing the desorption peak temperature. The surface of La–Sr–Co–Fe perovskite-type oxides was modified only with the polymerization initiator, (2-bromo-2-methyl)propionyloxyhexyltriethoxysilane (BHE) because there is no direct interaction between the polymer-brush and the substrate, while the initiator is directly modified to the substrate. The oxygen desorption behavior of BHE-modified oxides indicates that its oxygen desorption property is impeded without modification with PMMA. The investigation of BHE-modified oxide cation chemical states and oxygen desorption behaviors imply that the BHE-modifying site and change in chemical states have selectivity depending on cation species. Although sintering causes the formation of silicate and ceramic decomposition, this step can eliminate the harmful effects of BHE-modification in total. When conventional La–Sr–Co–Fe perovskite-type ceramics are used, sintering is preferable for the recovery of thin-film surface reactions. However, if we utilize site selectivity of BHE-modification, the harmful effects of those modifications can be avoided by modifying BHE onto sites that hardly participate in surface reactions.     

氧化石墨烯在燃料电池质子交换膜中的应用

保护环境，开发环保型能源，对人类和社会具有重要意义。质子交换膜燃料电池由于其能量转化率高，可实现零排放，近年来引起了电池领域研究者们的兴趣。氧化石墨烯（GO）由于存在活性氧官能团，可以和离子型聚合物进行复合以制备复合质子交换膜。氧化石墨烯类的复合质子交换膜应用于燃料电池时可以提高膜在高温低湿度条件下的质子传导率，降低甲醇渗透率，提高电池的功率密度。本文首先介绍了氧化石墨烯的制备方法，然后从不同的离子型聚合物基质复合质子交换膜的类别出发，详细介绍了氧化石墨烯在Nafion、聚醚醚酮、聚苯并咪唑和壳聚糖等不同种类的离子型聚合物中的应用现状及作用机理，同时对其在质子交换膜的应用方面存在的问题及应用前景做了评论和展望。     

Pore orientation of the gadolinia‐doped ceria cathode interlayer for a tubular SOFC using dip‐coating

An active region of cathode interlayer in a tubular solid oxide fuel cell (SOFC) is structurally analyzed using a dual‐beam focused ion beam/scanning electron microscope (FIB/SEM). The GDC (10 mol% gadolinia‐doped ceria) cathode interlayer (about 1 μm in thickness) is dip‐coated, and then sintered on YSZ (8 mol% yttria‐stabilized zirconia) electrolyte. At 1150°C sintering temperature, the pores oriented more along the axial direction than the radial direction. The anisotropy of pore shape is accounted for the withdrawal force during the dip‐coating of the GDC interlayer.     

Advances in novel SDC@Al2O3 core−shell electrolyte for low-temperature solid oxide fuel cell

The preparation of electrolyte with excellent ionic conduction is an important development direction in the practical application of solid oxide fuel cell (SOFC). Traditional methods to improve ion conduction was structure doping to develop electrolyte materials. In this work, the ionic conductor Ce_0.8Sm_0.2O_2-δ (SDC) was modified by insulator Al₂O₃ to enhance ion conduction and apply as electrolytes for the SOFC. The transmission electron microscopy (TEM) characterization clearly clarified that a thin Al₂O₃ layer in the amorphous state coated on SDC to form the SDC@Al₂O₃ core−shell structure. The SDC@Al₂O₃ electrolyte with the core−shell structure possesses a super ionic conductivity of 0.096 S cm⁻¹ and results in advanced cell performance of 1190 mW cm⁻² at 550°C. The X-ray photoelectron spectroscopy (XPS) analysis revealed that the concentration of oxygen vacancies in the SDC@Al₂O₃ core–shell structure significantly improved in comparison with pure SDC, the newly produced oxygen vacancies can promote the oxygen ion transport. Moreover, the interface between SDC and Al₂O₃ provides a fast channel for the proton transport. In addition, the SDC-based SOFC was usually suffered from the reduction of the SDC electrolyte and the accompanying generated electron conduction should deteriorate the cell performance, this is the main challenge for the SDC electrolyte application. In our case, the Al₂O₃ shell on the SDC surface not only can avoid the contact between SDC and hydrogen to eliminate the reduction of SDC but also can restrain electron conduction due to the electron insulation characteristic of the Al₂O₃ shell. This work demonstrates an efficient approach to develop the advanced low-temperature SOFC technology from material fundamentals.     

Ionic interactions and transport mechanism in polyurethane electrolytes

Alternating current (AC) impedance, Fourier transform (FT)–Raman, and Fourier transform infrared (FTIR) have been conducted on solutions of poly(ethylene oxide)_(MW=1000)–urethane electrolytes commingled with LiCF₃SO₃ as the function of temperature and salt concentration. From the analysis of the Vs(SO₃) vibration, the ionic concentration of salt in various chemical environments can be calculated approximately. The spectroscopic evidence was found for the redissociated ion pairs, and ionic congeries increased with increasing temperature. AC impedance measurements is used to calculate the ionic diffusion coefficient (D_i). Investigated the various concentrations (from O/Li = 4 ～ 20) at the different temperature (40 ～ 120°C), We found that the calculated values (D_i) with the Nernst–Einstein equation are higher than the direct measurement. The discrepancy increases with the increase of temperature. A good correlation between the conductivity and the ionic redissociation is determined from the Vs(SO₃) vibration band. The fraction of the “free” ion significantly corresponds to the revised Nernst–Einstein equation by using the Nernst–Einstein relation and compared with those direct measurement. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 785–790, 2002     

SOFC单相氧化物MIEC阳极材料的研究进展

综述了近年来国内外固体氧化物燃料电池复合导电性能(MIEC)单相氧化物阳极材料的研究进展。阐述了钙钛矿结构、立方萤石结构以及其它诸如烧绿石结构的单相氧化物阳极材料的导电性能以及应用于电池阳极的发电性能。指出了阳极材料研究亟待解决的问题及发展方向。     

Densification and electrical conductivity of Fe and Mn-doped Ce0.83Sm0.085Nd0.085O2-& by solid-liquid method

Fe and Mn-doped Ce_0.83Sm_0.085Nd_0.085O_2-& (SNDC) powders are successfully synthesized by the simple and efficient solid-liquid method. The crystallinity and morphologies of the powders were characterized by X-ray diffractometer, Raman spectrum, and scanning electron microscopy. The effect of doping on sintering behavior, grain interior, and grain boundary conductivity are studied. The doping of Fe can effectively reduce the sintering temperature from 1450^oC to 1250°C and keep the same density. Compared with SNDC, 1 mol% Fe-doped SNDC (Fe-SNDC) sintered at 1250°C shows a higher total conductivity of 2.13 × 10⁻² S·cm^-1 at 650°C. Also, it exhibits that doping of Fe can increase the conductivity of grain interior and grain boundary simultaneously. The present work shows that the Fe-SNDC synthesized by solid-liquid method can be used as a potential electrolyte for intermediate-temperature solid oxide fuel cells.     

Interaction of a ceria‐based anode functional layer with a stabilized zirconia electrolyte: Considerations from a materials perspective

We report on the materials interaction of gadolinium‐doped ceria (GDC) and yttria‐stabilized zirconia (YSZ) in the context of high‐temperature sintering during manufacturing of anode supported solid oxide fuel cells (AS–SOFC). While ceria‐based anodes are expected to show superior electrochemical performance and enhanced sulfur and coking tolerance in comparison to zirconia‐based anodes, we demonstrate that the incorporation of a Ni–GDC anode into an ASC with YSZ electrolyte decreases the performance of the ASC by approximately 50% compared to the standard Ni–YSZ cell. The performance loss is attributed to interdiffusion of ceria and zirconia during cell fabrication, which is investigated using powder mixtures and demonstrated to be more severe in the presence of NiO. We examine the physical properties of a GDC–YSZ mixed phase under reducing conditions in detail regarding ionic and electronic conductivity as well as reducibility, and discuss the expected impact of cation intermixing between anode and electrolyte.     

固体氧化物燃料电池CuCoNi/SDC阳极微结构与电性能的研究

本论文采用溶胶-凝胶低温燃烧合成法制作CuxCo0.5-xNi0.5O1.75-0.5x固溶体阳极粉末,并将电解质粉末和阳极合金粉末按1:1的比例制作了CuCoNi/SDC阳极片。采用热重差热仪检测粉末的处理情况,采用x射线衍射仪(XRD)检测了粉末的成相情况。并且采用四端子法检测了不同组成阳极片的电导率值。分析了固体氧化物燃料电池CuCoNi/SDC阳极的显微结构。结果显示,用上述方法合成的粉体成相很好,阳极片的电导率和组成、温度有着极强的联系,氢气还原前后微结构有明显的变化。     

Imidazolium ionic liquid incorporation on sulfonated poly(styrene‐isobutylene‐styrene) proton exchange membranes

Ionic liquids (ILs) with different anions and cations were incorporated in sulfonated poly(styrene‐isobutylene‐styrene) (SIBS) to modify its chemical, morphological, and transport properties for direct methanol fuel cell (DMFC) applications. Different loadings of IL and different solvents were studied to have a better understanding of the incorporation process and the ability of the solvent to affect the interaction of the IL with the sulfonated polymer. Morphological characterization with SAXS and AFM suggested changes caused by the incorporation of the IL and by the solvent used. FT‐IR spectra showed small variations in energy related to interactions of the IL with the sulfonic groups which caused thermogravimetric stabilization of the ionic domains. Other results suggest that water has a very significant effect on the morphology, interaction with the IL, and transport properties of the membranes. Optimal concentration of IL (～10 mol %) provides enough water to produce efficient proton conductivity (0.15 S/cm) and minimal methanol permeability (0.8 × 10^?6 cm²/s). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44900.     

The improving thick film properties of Er2O3 doping fcc-ZrO2 type solid electrolyte for SOFC applications

In this study, the binary system of (ZrO₂)_1-x(Er₂O₃)_x was investigated in the doping range of x; 0.02 ≤ x ≤ 0.12 by the Pechini method. According to X-ray diffraction (XRD) measurement results, Er₂O₃ doping face-centered cubic (fcc) ZrO₂-based solid solution was stabilized in the doping range of 0.08 ≤ x ≤ 0.12 at 1200°C for 12 hours. Thick films of fcc-ZrO₂ type powders were produced using ethyl cellulose organic binder mixture and spin-coating method. The crystallographic, microstructural, and electrical conductivity properties of the thick films were characterized via XRD, SEM, and a.c. impedance measurements, respectively. 8-ESZ ((ZrO₂)_1-x(Er₂O₃)_x, x = 0.08) thick film electrolyte showed the highest electrical conduction level which is 2.51 × 10⁻² ohm⁻¹ cm⁻¹ at 850°C under 150 mL min⁻¹ O₂ volumetric flow rate. All thick film properties of fcc-ESZ materials were optimized and improved experimentally for using as a solid electrolyte component in solid oxide fuel cell (SOFC) systems. A pre-treatment of 8-ESZ and the cathode-supported type electrochemical cell were primarily fabricated. The power density measurements of 40-LNF (LaNi_1-xFe_xO₃, x = 0.4) Cathode|Cathode Active (50:50 wt % 40-LNF:8-ESZ)| 8-ESZ Electrolyte|Anode Active (60:40 wt % NiO:8-ESZ)|NiO Anode Electrode cell stack suggest that the produced electrolytes had the usefully properties for SOFC applications.     

用于质子交换膜燃料电池的高温无机质子传导材料研究进展

质子交换膜是质子交换膜燃料电池（PEMFC）的核心部件，其主要作用是传导质子。无机质子传导材料作为一种新型的质子传导介质，近年来逐渐引起了人们的关注。本文主要介绍了小分子磷酸、无机沸石材料、固体酸和无机氧化物陶瓷材料等几种高温无机质子传导材料，并对它们的性能和特点进行了评述。主要结论如下：小分子磷酸质子传导率高，但是容易泄露；无机沸石材料化学稳定性好，但质子传导率尚有提高的空间；无机氧化物陶瓷材料力学性能和化学温度性能均很好，但质子传导率相对较低；固体酸质子传导率优异，高温稳定性也好，是最有希望在PEMFC中获得推广应用的材料。     

中低温固体氧化物燃料电池陶瓷阴极材料

综述了中低温固体氧化物燃料电池（SOFC）陶瓷阴极材料的研究和发展动态，这些陶瓷材料包括焦绿石结构的A2Ru2O7-δ陶瓷，Ag-YDB(Y2O3dopedBi2O3)复合陶瓷以及具有钙钛矿结构的La1-xSrxCo1-yFeyO3(LSCF)型陶瓷。     

造孔剂含量对固体氧化物燃料电池阳极的结构与电性能的影响

通过向阳极添加造孔剂（PMMA）改善阳极的微观结构,研究不同含量的造孔剂（PMMA）对阳极的显微结构、电性能的影响。利用SEM、电化学1二作站等测试手段对单电池的结构和电性能进行了表征。研究结果表明,添加7wt．％的PMMA造孔剂制备的单电池,阳极的孔隙率高,阳极中的气孔分布均匀,结构规整,降低了燃料气的传输阻力,提高了三相反应界面,获得了良好的电性能。以H2＋3％H：0为燃料气,在750℃下单电池的开路电压（OCV）为1．08V、最大功率密度为0．82W／cm2、欧姆阻抗为0．20Ω·cm2、两极阻抗为0．53Ω·cm2。     

固体氧化物燃料电池阴极材料的研究进展

简述了固体氧化物燃料电池阴极材料研究近况及重要进展。     

Improvement of Mechanical and Electrical Properties of Scandia-Doped Zirconia Ceramics by Post-Sintering with Hot Isostatic Pressing

Significant improvement in the fracture strength, accompanied by an enhancement in the electrical conductivity, of zirconia polycrystals that were doped with 3–7 mol% Sc₂O₃ was obtained by sintering at 1300°C for 1 h in air, followed by hot isostatic pressing (HIP) at 196 MPa at 1300° and 1450°C for 1.5 h in an argon-gas atmosphere. Dense bodies (with an average grain size of <0.5 μm) that were doped with 3.5 mol% of Sc₂O₃ showed the highest average fracture strength up to 1770 MPa and an electrical conductivity of 0.08 S/cm at 1000°C. The present zirconia ceramics, which consisted of submicrometer-sized grains of tetragonal phases and were stabilized with 5 and 6 mol% of Sc₂O₃, exhibited high strength (1330 and 1140 MPa, respectively) and good conductivity (0.15 and 0.18 S/cm, respectively); values for both properties were greater than those previously reported. The present HIPed zirconia ceramics, which have excellent properties, are candidates for an electrolyte of planar-type solid oxide fuel cells.