陶瓷学报2025，Vol.46Issue(1)：96-105,10.DOI:10.13957/j.cnki.tcxb.2025.01.008
高熵合金反应共烧保护层/接触层双层结构在SOFC阴极侧的应用
Co-Sintering of High-entropy Alloy Derived Coating/Contact Dual-Layer Structure for Application of SOFC at Cathode-Side
摘要
Abstract
[Background and purpose]Solid oxide fuel cell(SOFC)is a highly efficient electrochemical device that can be used to directly convert chemical energy of hydrogen and hydrocarbon fuels into electricity in an environmentally friendly manner.While the typical operating temperatures of SOFCs have been reduced to 600-850 ℃,ferritic stainless steels(FSS),such as ZMG 232,AISI 441,SUS430,etc.,can be utilized as interconnect materials,due to their high electrical conductivity,low material/manufacturing cost,excellent mechanic strength and similar coefficient of thermal expansion(CTE)to other cell components.However,it still exists several issues during their operation at 600-850 ℃,including continuous growth of Cr2O3 scale,Cr migration to cathode and dimensional tolerance at interconnect-cathode interface.These issues will cause serious performance degradation for stacks.To solve these problems,a dense protective coating and a porous contact layer are typically prepared between the metallic interconnect and the cathode.The dense protective coating is utilized to inhibit the growth of Cr2O3 scale and prevent Cr migration to the cathode,while the porous contact layer can provide better electrical pathway to decrease the power losses and compensate for the dimensional tolerance between the interconnect and the cathode. [Methods]In this study,MnCoNiFeCu alloy powder was selected as the precursor materials for dense protective coating and porous contact layer.A coating/contact dual-layer structure was fabricated through reactive co-sintering in the simulated SUS 430 interconnect/coating/contact/cathode/cathode support test cells.The precursors were calcined in air at 900 ℃ for 2 h to study phase evolution and microstructure of the protective coating and the contact layer.The phases in the sintered layers were characterized by using X-ray diffraction(XRD),whereas scanning electron microscopy(SEM)featured with energy-dispersive spectroscopy(EDS)was utilized to analyze the microstructure and obtain the compositional information.The test cells were fabricated to examine the electrical performance of the dual-layer structure via Area-Specific Resistance(ASR).After the initial sintering,the furnace temperature was then dropped to 800 ℃ for isothermal oxidation for 1000 h and ten thermal cyclic test.The tested samples were then epoxy-mounted,sectioned,and polished for examining cross-sectional microstructure after oxidation.EDS line scans near at the interconnect-coating and contact-LSM cathode interfaces were obtained to identify the possible interdiffusion between the cell components.Furthermore,the effectiveness of the dual layer in inhibiting the growth of the Cr2O3 layer and blocking Cr migration from the interconnect to cathode was also assessed. [Results]XRD results of the protective coating and contact layer after thermal conversion revealed that the sintered samples predominantly consisted of spinel phase,with minor oxides,while no metallic phases were detected.Specifically,the protective coating exhibited a majority of the spinel phase along with CuO and CoO,as confirmed by EDS mappings,indicating the aggregation of Cu and Co on the surface.In contrast,the contact layer primarily contained the spinel phase and CuO,with EDS mappings indicating uniform distribution of Fe,Co,Ni,Mn and Cu,while no delamination was observed.In ASR measurements,the tested sample exhibited stable behavior with an ASR of only 22.04-22.71 mΩ·cm2 during the 1000 h isothermal oxidation,while the thermal cycling led a dramatic increase in ASR.Once the ASR measurement was completed,the sample cross-sectional surface was characterized.For isothermal oxidation,a dense protective coating and a relatively porous contact layer were observed between the interconnect and cathode.The dual-layer structure was well-boned with the interconnect and cathode after the isothermal oxidation,indicating that the double-layer structure exhibited exceptional thermal compatibility with the adjacent cell components.Importantly,no Cr was detected within both the contact layer and cathode,further confirming the effectiveness of the double-layer structure in inhibiting the migration of Cr from the interconnect to cathode.Conversely,the thermal cycling test sample exhibited serious cracking at the interface between the porous contact layer and the LSM cathode,which was responsible for the rapid increase in ASR during thermal cycling testing. [Conclusions]In this study,MnCoNiFeCu alloy powder was utilized as the precursor material to develop a dense protective coating and a porous contact layer simultaneously through reactive co-sintering,forming a(Mn,Co,Ni,Fe,Co)3O4-based dual-layer structure.The sample exhibited stable behavior with an ASR of only 22.04-22.71 mΩ·cm2 after 1000 h of isothermal oxidation,while the thermal cycling led a dramatic increase ASR in.Notably,the growth of the Cr2O3 scale was dramatically suppressed,while no Cr was detected in the LSM cathode,confirming the effectiveness of the thermally converted dual-layer structure in blocking the migration of Cr.The HEA used as the dense protective coating and porous contact layer offers several advantages,including uniform microstructure,improved electrical performance,exceptional Cr-blocking capability and simple fabrication process.In the future study,more efforts should focus on optimizing the elements in the precursor alloy to further enhance the uniformity and CTE matching of the dual-layer structure after sintering.关键词
固体氧化物燃料电池/高熵尖晶石/反应共烧/尖晶石/双层结构Key words
solid oxide fuel cell/high-entropy alloy/reactive co-sintering/spinel/dual-layer structure分类
化学化工引用本文复制引用
陈帮富,陈云霞,余喻天,吴博,林囿辰,刘青,关成志,王建强..高熵合金反应共烧保护层/接触层双层结构在SOFC阴极侧的应用[J].陶瓷学报,2025,46(1):96-105,10.基金项目
中国科学院前瞻战略科技先导专项(XDA0400000) （XDA0400000）
上海市嘉定区科技创新"揭榜挂帅"项目 （）
上海市2023年度"科技创新行动计划"科技支撑碳达峰碳中和项目(23DZ1201803) （23DZ1201803）
江西省科技合作计划重点项目(20212BDH80005) （20212BDH80005）
上海市科技计划项目(21DZ1207700). （21DZ1207700）
