固体氧化物燃料电池合金连接体涂层材料研究进展

固体氧化物燃料电池(SOFC)向中温化发展,使得用金属材料作连接体成为可能.但是金属连接体在SOFC工作的高温氧化和湿氢环境中,其使用寿命受到严重限制,需要表面保护层.常用钙钛矿结构和尖晶石结构类的氧化物作为金属涂层材料.在合金表面涂覆致密氧化物涂层很关键,通过涂层材料与合金挥发出的Cr类元素之间的化学反应,可以降低Cr挥发,减弱Cr对阴极的毒化,阻止合金的进一步氧化.涂层材料还需要有高的电子电导率,与合金匹配的热膨胀性能,以降低界面电阻,防止涂层脱落.目前,还没有哪一种材料能够满足这多方面的要求,因此合金保护涂层材料还需要进一步的研究.     

固体氧化物燃料电池/电解池金属连接体涂层研究进展

可逆固体氧化物池(SOC)既可作为燃料电池(SOFC)发电,又可用作电解池(SOEC)制氢或合成气,用于清洁能源转换和存储。涂层制备技术对SOC电堆的发展尤为重要。本研究对SOC在不同操作模式下的工作环境进行了分析,对SOC电堆连接体可用的合金材料、涂层材料和涂层制备技术进行了综述。     

固体氧化物燃料电池金属连接体保护膜层研究进展

随着固体氧化物燃料电池(SOFC)的工作温度从1000℃降低到600~800℃,铁素体不锈钢成为SOFC连接体材料的最佳选择,但在高温氧化气氛下,氧化层快速生长以及Cr的毒化问题使得电池堆性能大大降低。目前,主要的解决方式是在基体材料表面涂镀保护膜层和材料改性。前者由于生产简单、成本低成为当前研究热点。本文主要介绍金属连接体保护膜的分类和研究现状,并探讨各膜层材料的优缺点及发展前景。     

固体氧化物燃料电池金属连接体腐蚀研究进展

固体氧化物燃料电池(SOFC)常用廉价、易加工、导电性强的铁素体不锈钢作为连接体材料。然而,SOFC电堆中苛刻环境限制连接体的使用。本文介绍了近年来连接体材料腐蚀行为的研究现状,综述了空气、燃料气氛、双重气氛、微量合金元素、接触环境等因素对连接体腐蚀的影响规律,系统地阐述了连接体材料的腐蚀机理,并指出连接体腐蚀行为研究中存在的不足以及未来发展方向。     

固体氧化物燃料电池金属连接体防护涂层研究进展

铁素体不锈钢因具有良好的耐腐蚀性、高电导率、高热导率等诸多优异性能,是常用的中低温固体氧化物燃料电池（SOFC）用连接体材料,但是含Cr不锈钢在600～800℃的SOFC工作温度下存在高温氧化带来的界面电阻增大、Cr元素毒化阴极等问题。从连接体材料、防护涂层种类及其制备方法出发,简述了金属连接体材料的选择和Cr毒化阴极机理,重点阐述了活性元素氧化物涂层、稀土钙钛矿涂层以及尖晶石涂层对连接体的保护作用和近些年新的研究进展,并归纳了SOFC金属连接体表面涂层常用的制备方法和特点。介绍了稀土元素氧化物涂层对合金氧化膜的影响机制和应用局限性。总结了La_1–xSr_xCrO₃、La_1–xSr_xCoO₃、La_1–xSr_xMnO₃等常用钙钛矿涂层的优势和不足,并分析了掺杂对钙钛矿涂层性能的影响。重点综述了过渡金属元素掺杂、稀土元素掺杂对Mn-Co、Cu-Mn尖晶石涂层电导率、热膨胀系数匹配性、涂层结合情况等...     

固体氧化物燃料电池连接体材料研究进展

固体氧化物燃料电池(SOFC)是高效、洁净、全固态的电化学装置,是发展比较快的能源技术之一.本文总结了SOFC关键组件连接体材料的研究进展,详细论述了近年发展起来的金属连接体材料的研究状况,总结了目前研究比较广泛的Ni基、Fe基、Cr基连接体合金的性能特点和存在的主要问题,最后介绍了经过表面处理的Fe-Cr基合金应作为SOFC金属连接体材料的研究重点.     

固体氧化物燃料电池(SOFC)合金连接体耐高温氧化导电防护涂层

降低固体氧化物燃料电池(SOFC)工作温度,可使用高电导、高热导、高强度的合金作为连接体。其中含Cr的铁素体不锈钢合金,具有与SOFC其他部件材料匹配的热膨胀系数,此外还有易于加工及成本低廉等优点,成为中低温板式SOFC连接体材料应用与研究的重点。但这类合金表面高温氧化所带来的界面电阻变化,及Cr挥发进而在阴极沉积所带来的诸多问题,成为影响板式SOFC长期稳定的关键因素,因此必须进行有效的表面处理。从SOFC合金连接体引起的电堆性能衰减机理出发,阐明了降低或防止阴极Cr中毒的几类方法,论述了合金连接体涂层的必要性。结合笔者开发设计的尖晶石粉末还原法在合金连接体表面制备纳米微结构Mn_(0.9)Y_(0.1)Co_2O_4(MYC)防护涂层方面的工作,综述了国内外SOFC合金连接体涂层材料及涂层制备方法的研究进展。对各类涂层材料及涂层制备方法优缺点进行比较的同时,重点介绍了电导率高、实用性较强的钙钛矿结构及尖晶石结构涂层材料。最后展望了合金连接体涂层的发展前景。     

涂层材料在固体氧化物电池金属连接体上的应用

系统地论述了应用于固体氧化物燃料电池(SOFC)连接体的各种涂层材料,总结了涂层在应用过程中存在的问题,并提出了建议.     

先进陶瓷涂层结构调控及其在固体氧化物燃料电池中的应用

等离子喷涂技术可以对陶瓷涂层的微观结构进行调控设计,因此在制备固体氧化物燃料电池方面具有独特的优势。基于等离子喷涂方法,可以直接制备或经过后处理获得致密的电解质涂层。采用等离子喷涂技术也可以制备高性能的多孔阳极和阴极,并可对钙钛矿结构阴极材料的成分和晶体结构进行调控。文中介绍了目前国内外采用涂层制备电池的方法,主要探讨了热喷涂方法制备电解质涂层的特点,对存在的问题和可行思路进行了讨论,并探讨了基于提高三相反应界面长度来制备高性能电极的方法。由于固体氧化物燃料全电池各功能层都有可能通过热喷涂方法制备,因此该方法在固体氧化物燃料电池结构设计具有巨大的潜力。     

等离子喷涂技术在固体氧化物燃料电池中的应用

介绍了等离子喷涂制备固体氧化物燃料电池（SOFC）中的电解质、阴阳极及其功能组件的研究进展,分析了其中的关键技术.研究表明：采用等离子喷涂,通过选择适当的粉末原料,工艺优化和改进送粉方式,可以得到满足SOFC要求的致密电解质,多孔阴极和阳极.三者的厚度均为30～50 μm,SOFC总厚度低于100～120μm,可以将固体氧化物燃料电池的运行温度降低到中温800℃下的范围,降低电池运行温度,从而降低了对相关材料的要求和运行成本.     

Metallic interconnects for solid oxide fuel cell: Performance of reactive element oxide coating during long time exposure

One of challenges in improving the performance and cost‐effectiveness of SOFCs (solid oxide fuel cells) is the development of suitable interconnects materials. Chromia‐forming alloys and especially ferritic stainless steels, like Crofer22APU, are considered to be among the most promising candidate materials as interconnects in SOFC stacks. However, the performance of chromia‐forming materials can be limited by the low electronic conductivity of the oxide scale (high ASR – area specific resistance – value). Such degradation are unacceptable regarding the long‐term operation (>40 000 h). A previous study 1 demonstrated that in air, the addition of a nanometric reactive element oxide (La₂O₃) layer applied by metal organic chemical vapor deposition (MOCVD) drastically improved both corrosion rate and electrical properties of Crofer22APU and Haynes230 alloys for 100 h at 800 °C. In this present study coating performances were checked after 10 months (7500 h) and 20 months (15 000 h) at 800 °C in air. The corrosion products were carefully analyzed by SEM, EDX, and XRD. ASR measurements are realized after long time exposure. This study demonstrates that the Crofer22APU alloy has a good oxidation resistance after 15 000 h in air but this alloy has an ASR value equal to 0.370 Ω cm². The coatings composed of a thin reactive element oxide such as La₂O₃ resulted in an important improvement in the high temperature oxidation resistance; the ASR values are equal to 0.154 Ω cm². Haynes230 alloy has a better oxidation resistance but the formation of an insulating Al₂O₃/SiO₂ layer could be detrimental.     

Development of metallic substrate supported planar solid oxide fuel cells fabricated by atmospheric plasma spraying

A planar solid oxide fuel cell (SOFC) consisting of a cell supported with a porous metallic substrate and a metallic separator has been developed. In the fabrication of the cell, anodes and electrolytes were formed on sintered Ni-felt substrates using flame spraying (FS) and atmospheric plasma spraying (APS), respectively. The APS is also applied to form (LaSr)MnO₃ protective coatings on the metallic separators. With these metallic cells and separators, a 3 kW-class stack, which consisted of 30 cells (15-cell block×2) was constructed and operated. The active electrode area of the cell was 600 cm². The stack generated 3.3 kW at 970 °C when the current density was 0.3 Acm⁻² and the fuel utilization 50%. It did not show any degradation for the initial 2100 h, but a few cells in the lower 15-cell block became unstable after 2100 h. On the other hand, the upper 15-cell block was stably operated for 3200 h.     

Thermal stability and oxidation resistance of TiCrAlYO coatings on SS430 for solid oxide fuel cell interconnect applications

Chromia-forming ferritic stainless steels are being considered for interconnect applications in planar solid oxide fuel cell (SOFC) stacks because of their low cost and physical properties. At high temperatures, ferritic steels lack environmental stability in the SOFC operating environment, and gradually degrade the cell stack performance. In this study, an effective, dense and well adherent TiCrAlYO coating was deposited on an SS430 alloy using the filtered arc deposition technique. High-energy ion backscattering was used to characterize the composition and the thermal stability of the coatings. The chromium volatility of the coated steel plates at 800 °C was also measured using ion beam analysis. Significant reductions in oxidation rates as well as reduced Cr volatility were observed for the coated alloys.     

Using CrAlN multilayer coatings to improve oxidation resistance of steel interconnects for solid oxide fuel cell stacks

The requirements of low-cost and high-temperature corrosion resistance for bipolar interconnect plates in solid oxide fuel cell stacks has directed attention to the use of metal plates with oxidation resistant coatings. The performance of steel plates with multilayer coatings, consisting of CrN for electrical conductivity and CrAlN for oxidation resistance, was investigated. The coatings were deposited using large area filtered arc deposition technology, and subsequently annealed in air for up to 25 hours at 800 °C. The composition, structure, and morphology of the coated plates were characterized using Rutherford backscattering, nuclear reaction analysis, atomic force microscopy, and transmission electron microscopy techniques. By altering the architecture of the layers within the coatings, the rate of oxidation was reduced by more than an order of magnitude. Electrical resistance was measured at room temperature. This paper was presented at the Fuel Cells: Materials, Processing, and Manufacturing Technologies Symposium sponsored by the Energy/Utilities Industrial Sector & Ground Transportation Industrial Sector and the Specialty Materials Critical Technologies Sector at the ASM International Materials Solutions Conference, October 13–15, 2003, in Pittsburgh, PA. The symposium was organized by P. Singh, Pacific Northwest National Laboratory, S.C. Deevi, Philip Morris USA, T. Armstrong, Oak Ridge National Laboratory, and T. Dubois, U.S. Army CECOM.     

中温固体氧化物燃料电池新型连接体材料的研制

以SUS430不锈钢粉末和具有钙钛矿结构的La0.8Sr0.2FeO3(LSF)陶瓷粉末为原料,通过粉末冶金方法制得了SUS430/LSF双层复合试样.对烧结SUS430不锈钢和LSF试样的密度和相组成进行了测试;通过氧化增重法测算了SUS430不锈钢及SUS430/LSF双层结构材料的氧化速率常数;采用四探针法对SUS430不锈钢及SUS430/LSF双层结构材料的面比电阻进行了测试;并对氧化前后材料的微观组织进行了观测.结果表明,采用本实验方法可以在烧结不锈钢基体表面制得致密的LSF涂层;在循环氧化过程中,LSF涂层与不锈钢基体结合牢固.SUS430/LSF双层结构材料在空气中于800 ℃氧化150 h后,氧化速率常数为2.81×10-15 g2·cm-4·s-1,比SUS430不锈钢降低了一个数量级以上,而其面比电阻则由SUS430不锈钢的74.65 mΩ·cm2降为15.55 mΩ·cm2.     

Characterization of suspension plasma-sprayed solid oxide fuel cell electrodes

Suspension plasma spray is a promising technique that uses fine particles dispersed in a liquid as feedstock material instead of dry powder as in conventional plasma spraying and has been implemented here to produce layers with appropriate morphologies and microstructures for SOFC applications.This study uses a pressurized gas delivery system to feed the slurry through a homemade two-fluid atomizing nozzle to a conventional plasma torch. The electrodes consist of porous NiO-YSZ as anode and lanthanum nickelate as cathode. The anode and respectively the cathode were deposited onto dense or porous ferritic steel substrates in order to be characterized and optimized. The cell components were examined by scanning electron microscopy (SEM), X-ray diffraction and leakage test. This paper aims at studying the influence of the suspension characteristics (surface tension and viscosity were selected as main parameters), the conditions of injection (nozzle design, gas to liquid ratio, injection angle have been identified as major parameters), the plasma conditions (plasma gas nature and flow rates, spray distance are of major importance) and finally the kinematics on the crystalline phases, the chemical composition (distribution of NiO particles into the layer), the thickness and roughness, the pore ratio and the gas permeability. Then the optimized electrodes have been deposited onto ferritic substrate to perform Open Circuit Voltage and impedance tests at a temperature around 800 °C. This work demonstrated the feasibility for the fabrication of electrodes with interesting performance using suspension plasma spraying technique.     

Magnetron-sputtered cobalt-based protective coatings on ferritic steels for solid oxide fuel cell interconnect applications

Co, Co–Mn (67:33 at.%) and Co–Cu (67:33 at.%) coatings were fabricated using magnetron sputtering on two kinds of ferritic stainless steels (Crofer22APU and F17TNb) in order to form spinel protective coatings on metallic interconnects for solid oxide fuel cells. Despite the thickness unevenness at different regions, dense metallic coatings were successfully applied onto all necessary surfaces of the channelled interconnect substrates. Upon oxidation, spinel oxide coatings with very low Cr content were formed, reducing effectively the Cr release. Among the three protective coatings, Co–Cu coating showed the lowest area specific resistance (<15 mΩ cm² at 800 °C).     

等离子喷涂-物理气相沉积制备7YSZ纳米结构固体氧化物燃料电池电解质层

氧化钇稳定的氧化锆（YSZ）因其高热稳定性和良好的氧离子电导率被广泛地作为电解质材料应用于固体氧化物燃料电池（SOFC）。常规的平面SOFC电解质制备技术,如带式流延或丝网印刷,需要在1300℃以上的温度下进行烧结,因此采用传统制备技术获得纳米结构电解质层是一个挑战。等离子喷涂-物理气相沉积（PS-PVD）作为一种新技术由于可以实现气相沉积可以提供快速、低成本的方法来制备纳米致密结构电解质层,可避免传统技术在长时间高温烧结引起的材料晶体结构变化以及相邻电极材料间的化学反应。PS-PVD技术具有与传统大气等离子喷涂（APS）完全不同的沉积机制。本研究采用该技术成功地制备了致密的纳米结构7YSZ薄电解质层。当电解质层厚度为8.7～12.3 μm时,其泄露率为2.24～2.29 10-8 cm4gf-1s-1.