添加Li_2O对YSZ电解质性能影响

8%（摩尔分数,下同）Y2O3稳定的ZrO2（8YSZ）是固体氧化物燃料电池（SOFC）中最常用的电解质材料,本文研究了在8YSZ基体中加入n%Li2O（n=0,0.25,0.50,1.00,1.50,1.70,2.00,2.50,3.00）后（记为n%Li2OYSZ）对其晶相结构、晶格常数、烧结性能、微观形貌、电导率及其作为SOFC电解质性能的影响。结果表明,Li2O中的Li＋可以固溶到YSZ的晶格内使其晶格常数减小;Li2O的加入量n〈1.70时,瓷体在烧结过程中不会发生相变。加入少量的Li2O（n=0.25,0.50）可以提高YSZ的致密度和电导率,0.25%Li2OYSZ和0.50%Li2OYSZ样品800℃的电导率分别高达0.030 2 S/cm和0.027 6 S/cm,分别是纯YSZ的1.35和1.24倍;当Li2O含量n≥1.00时,相同条件下烧结体致密度随Li2O加入量的增大而逐渐减小;当n≥1.70时,样品在烧结过程中虽然出现相变,但在高于1400℃可以烧结致密,并得到纯立方相YSZ。将1250℃烧结制得的0.25%Li2OYSZ和0.50%Li2OYSZ作为SOFC电解质的单电池,800℃时的开路电压高于1.0V,说明YSZ中没有出现电子电导,具有比纯YSZ为电解质的单电池更高的性能输出,表现出了良好的应用前景。     

钙钛矿型中温固体电解质La0.9Sr0.1Ga0.8Mg0.2O3-δ的制备

以硝酸盐为前驱体合成了具有钙钛矿结构的中温固体电解质La0.9Sr0.1Ga0.8Mg0.2O3-δ(LSGM)。用XRD和SEM分析了样品钙钛矿相的形成过程和显微结构,用直流四电极法测试了电解质的氧离子电导率。研究结果表明:经1 450℃煅烧6 h后得到LSGM单相结构,800℃时的电导率为6.8×10-2S.cm-1,高于同温下钇稳定氧化锆(YSZ)样品的电导率,表明LSGM更适合做中温固体氧化物燃料电池(SOFC)的电解质材料。     

氧化钇稳定氧化锆的制备及电性能测试

氧化钇稳定氧化锆(yttria-stabilized zirconia,YSZ)是目前使用最多的电解质材料,探索了以YSZ纳米粉体为原料,采用固相法制备YSZ电解质薄片。采用X射线衍射(XRD)测试了它的微结构;采用交流四端子法测瓷体的电导率。实验表明,最佳烧结温度在1300℃,气孔含量少、晶粒均匀,电导率高,800℃时为0.08 S.m-1,是理想的高温电解质材料。     

添加3Y-TZP对8YSZ电解质材料的力学和电学性能的影响

采用机械混合方法,在8YSZ电解质材料中添加3Y-TZP,目的是在满足YSZ电解质电学性能要求的前提下,提高材料的力学性能.试样在常压下烧结,通过弯曲强度﹑断裂韧性﹑电导率测定和相组成分析,讨论了3Y-TZP添加量的影响.实验结果表明:加入3Y-TZP能显著提高陶瓷体的力学性能,弯曲强度和断裂韧性随着添加量的增多而提高;电学性能在0～30%(质量百分比,下同)的添加量时下降很小.添加30% 3Y-TZP的电解质材料在1000 ℃电导率为0.11 S/cm,强度接近300 MPa,综合效果最好.     

固体氧化物燃料电池电解质材料的研究进展

固体氧化物燃料电池(SOFC)被誉为21世纪最具有发展潜力的能源材料之一,它的热效率高、燃料的适应性强,能很好地满足区域供电、供热的需要,具有重要的经济和社会意义。本文综述了SOFC电解质的研究进展,指出在诸多的电解质材料中,尽管氧化铋系电解质拥有最高的电导率,但由于其化学稳定性很差,难以获得广泛的应用;氧化钇全稳定的氧化锆(YSZ)由于其中低温的电导率较低,只适用于高温SOFC;稀土掺杂的氧化铈和LaGaO3钙钛矿材料拥有较高的中低温电导率,性质较为稳定,是适用于中低温SOFC的电解质材料。     

流延法制备Ni-YSZ/YSZ复合基膜及性能测试

采用传统有机流延法制备NiO-YSZ/YSZ复合基膜,其中包括流延浆料配制及流延工艺过程.采用共烧结方式制备均匀平整的SOFC多孔阳极支撑的致密电解质膜,阳极支撑层厚度1000 μm、阳极功能层20 μm、致密电解质层40 μm左右.并对阳极孔隙率和电解质气体渗透率、显微结构及膨胀系数等进行测试.结果表明通过复合流延的方式可以制备出具有良好组织结构和性能的SOFC阳极支撑系统.     

NiO/YSZ浆料凝胶固化、干燥、排胶及烧结工艺研究

采用凝胶注模工艺制备固体氧化物燃料电池(SOFC)阳极材料NiO/YSZ是目前的研究热点之一.本文主要研究了凝胶注模工艺中引发剂和催化剂的加入量对凝胶固化时间的影响,干燥温度对坯体失重的影响,固相含量、造孔剂的种类及用量对瓷体收缩率的影响,并对还原后瓷体的电性能进行了表征.采用SEM、EDS方法分析表征样品.实验结果表明:在实验选定的100 mL浆料中,浓度为5wt%引发剂的加入量为2.0 mL,浓度为0.5vol%催化剂的加入体积量为1.0 mL,凝胶时间可以控制在20 min以内.NiO/YSZ阳极材料最佳干燥温度是25 ℃,固相含量为45vol%、采用15wt%石墨作为造孔剂,在1350 ℃烧成的NiO/YSZ阳极与固体电解质YSZ收缩率相匹配,氢气还原后NiO/YSZ阳极在600～800 ℃电导率达到800 S/cm,符合SOFC阳极材料电导率的要求.     

钛酸铝热分解的结晶形貌

以化学纯Al(OH)_3和试剂级TiO_2为原料,按Al_2TiO_5的化学计量组成将混合好的粉料在钢模中压制成10 mm×15 mm的试样,于大气条件下以1 600℃保温3 h烧结合成钛酸铝(AT);然后将烧结试样于大气条件下分别进行1 300℃保温3 h和1 000℃保温100 h的热处理,并利用XRD和FESEM-EDS鉴定AT热处理前后的显微结构。结果表明:1 600℃保温3 h合成的钛酸铝晶体形貌呈不规则粒状,尺寸约20μm,其晶间和晶内形成5～10μm气孔。烧结合成钛酸铝经1 300℃保温3 h热处理后,钛酸铝的晶体形貌不变,只是晶间微裂纹稍许扩展,而宏观结构几乎未变;经1 000℃保温100 h热处理时,钛酸铝分解成晶粒尺寸小于5μm的刚玉和小于10μm的金红石。EDS分析表明,刚玉可固溶3. 9%(w)的TiO_2,而金红石只固溶0. 3%(w)的Al_2O_3。     

纳米ScSZ基电解质中低温导电性研究进展

固体氧化物燃料电池（SOFC）适用于多种燃料气体,高效清洁,是最有前景的燃料电池之一。氧化钪（Sc₂O₃）掺杂二氧化锆（ZrO₂）系列（ScSZ）使氧化锆基电解质表现出优异的离子导电性。ScSZ基电解质晶粒纳米化呈现出了很好的电学性能而得到广泛深入的研究。但是ScSZ基电解质在中低温下会发生相变,产生低导电性的菱形相而影响其离子电导率。系统总结了单元或二元氧化物掺杂ScSZ电解质在中低温下的物相、晶体结构及电导率。多元氧化物复合掺杂ScSZ可有效防止在中低温下发生相变、稳定立方相ScSZ。采用不同方法制备纳米ScSZ基电解质,可很好地提高电解质的电导率。提出了ScSZ系列在中低温范围内（600~800 ℃）的发展方向：优化掺杂成分和掺杂量提高晶粒晶界电导率,使用不同工艺制备纳米电解质或不同制备方法制备新型结构电解质材料。     

热轧及再结晶退火对Mg-8Al-3.5Sr镁合金晶粒细化的影响

目前关于耐热镁合金的塑性变形及变形后的热处理工艺的基础研究相对较少,然而这又是镁工业发展的瓶颈,本文对铸态耐热Mg-8Al-3.5Sr镁合金固溶处理后进行不同压下量的热轧以及再结晶退火研究,利用光学显微镜和扫描电子显微镜研究试样的金相显微组织。研究结果表明:合金试样经380℃×24h固溶处理后显微组织内出现棒状Al4Sr相,晶界变得清晰可见且呈多边形化,平均晶粒尺寸为65μm;随热轧压下量的增加,平均晶粒尺寸呈下降趋势,压下量为80%时得到最佳显微组织,平均晶粒尺寸为26μm,当压下量继续增加到90%时,晶内出现大量裂纹;将该合金在300℃条件下保温1h,获得了等轴再结晶组织,平均晶粒尺寸进一步下降到21.5μm。再结晶退火温度过高时,晶粒呈现异常长大状态,同时会析出大量点状Mg17Al12相。     

Electrical conductivity of YSZ-SDC composite solid electrolyte synthesized via glycine-nitrate method

Yttria-stabilized zirconia (YSZ) is a common solid electrolyte for solid oxide fuel cells (SOFCs) because of its high electrical conductivity and high ionic transference number in both oxidizing and reducing atmospheres. Samarium doped ceria (SDC) has also been considered as an alternative electrolyte material to YSZ for intermediate temperature SOFC because of its high conductivity at relatively low temperatures. Due to improved ionic conductivity of YSZ at high temperature (~ 800 °C) and good conductivity of SDC in the intermediate temperature range (600–800 °C), the electrical properties of YSZ-SDC composites were investigated. Composites of YSZ and SDC with weight ratio 9.5:0.5, 9:1 and 8.5:1.5 were synthesized via glycine-nitrate route. XRD pattern of the systems revealed the formation of composite phases. Biphasic electrolyte microstructures were observed, in which SDC grains are dispersed in YSZ matrix. Relative density of the compositions was found to be more than 92% to the theoretical density. It was observed that the interface provides a channel for ionic transport, leading to a notable ionic conductivity. With increase in SDC weight ratio the electrical conductivity was found to increase. For weight ratio 8.5:1.5 the electrical conductivity was found to be greater than that of YSZ in the temperature range 400–700 °C. Further, for weight ratio more than 8.5:1.5, conductivity was found to decreases due to the formation of a few other insulating impurity phases. The electrode polarisation was also found to reduce significantly with SDC in the composite electrolyte system. Thus, such composite system may be useful for improving the ionic conductivity of the composite electrolytes.     

Development of a Novel Ceramic Support Layer for Planar Solid Oxide Cells

The conventional solid oxide cell is based on a Ni–YSZ support layer, placed on the fuel side of the cell, also known as the anode supported SOFC. An alternative design, based on a support of porous 3YSZ (3 mol.% Y₂O₃–doped ZrO₂), placed on the oxygen electrode side of the cell, is proposed. Electronic conductivity in the 3YSZ support is obtained post sintering by infiltrating LSC (La_0.6Sr_0.4Co_1.05O₃). The potential advantages of the proposed design is a strong cell, due to the base of a strong ceramic material (3YSZ is a partially stabilized zirconia), and that the LSC infiltration of the support can be done simultaneously with forming the oxygen electrode, since some of the best performing oxygen electrodes are based on infiltrated LSC. The potential of the proposed structure was investigated by testing the mechanical and electrical properties of the support layer. Comparable strength properties to the conventional Ni/YSZ support were seen, and sufficient and fairly stable conductivity of LSC infiltrated 3YSZ was observed. The conductivity of 8–15 S cm^–1 at 850 °C seen for over 600 h, corresponds to a serial resistance of less than 3.5 m Ω cm² of a 300 μm thick support layer.     

Gd2O3和Y2O3共掺CeO2基中温SOFC电解质材料的合成

采用固相合成法合成Gd2O3和Y2O3共掺CeO2基粉料[(CeO2)0.92(Y2O3)0.08-x(Gd2O3)x,x=0,0.02,0.04,0.06,0.08,摩尔分数,下同],在1 600 ℃烧成制备固态氧化物燃料池(solid oxide fuel cells,SOFC)电解材料.采用X射线衍射仪、热膨胀测...     

Fabrication of electrolyte materials for solid oxide fuel cells by tape-casting

In this research, solid oxide fuel cell electrolytes were fabricated by aqueous tape-casting technique. The basic compositions for SOFC electrolyte systems were focused on yttria-stabilized zirconia (YSZ) system. The powders used in this study were from different sources. ZrO₂-based system doped with 3, 8, and 10 mol% of Y₂O₃, and 8YSZ electrolyte tape illustrated the desirable properties. The grain size of the sintered electrolyte tapes was in the range of 0.5–1 μm with 98–99% of theoretical density. Phase and crystal structure showed the pure cubic fluorite structure for 8–10 mol% YSZ and tetragonal phase for 3 mol% doped. The electrolyte tapes sintered at 1450 °C for 4 h had the highest ionic conductivity of 30.11 × 10⁻³ S/cm which was measured at 600 °C. The flexural strengths were in the range of 100–180 MPa for 8–10 mol% YSZ, and 400–680 MPa for 3 mol% YSZ.     

Predictions on conductivity and mechanical property evolutions of yttria-stabilized zirconia in solid oxide fuel cells based on phase-field modeling of cubic-tetragonal phase transformation

Solid oxide fuel cell (SOFC) recently emerges as a promising power production technology with high efficiency. However, the degradation of yttria-stabilized zirconia (YSZ) electrolyte, brought by the cubic-tetragonal (c-t) phase transformation, remains a critical issue. Here, the c-t phase transformation of YSZ and its influences on the SOFC are quantitively investigated. First, micro-Raman spectroscopy characterization validates the occurrence of the c-t phase transformation during long-term operation. A microelasticity phase-field model is then built to simulate the phase transformation. The effects of variant nuclei and the misorientation angle between adjacent grains are investigated first based on both single-crystal and double-crystal systems. Subsequently, the phase-field model is applied on the 3D reconstructed real microstructure of polycrystalline YSZ. The results indicate that larger misorientation angles between adjacent grains suppress the development of the variants, and thus benefit in maintaining the ionic conductivity of the electrolyte and the mechanical strength of SOFCs.     

ZnO对8YSZ电解质材料的烧结性与电化学性能的影响

用机械混合方法,在8%(摩尔分数,下同)Y2O3稳定的ZrO2(8%in mole yttria stabilized zirconia,8YSZ)中添加ZnO量分别为0,1%,2%,3%,4%,在不同温度下常压烧结制备了ZnO:8YSZ电解质。研究了烧结温度和ZnO含量对ZnO:8YSZ样品的烧结性、致密度、弯曲强度和电导率的影响。由ZnO:8YSZ电解质作为支撑组装了单电池,对电池的性能进行测试和评价。结果表明:在8YSZ中添加ZnO能改善8YSZ材料的烧结性,1400℃烧结2h的4%ZnO:8YSZ样品的致密度达99.9%,3%ZnO:8YSZ样品的弯曲强度超过200MPa,获得明显提高。4%ZnO:8YSZ样品在800℃下的电导率达1.68×10-2S/cm。在相同工作条件下,ZnO:8YSZ单电池比8YSZ单电池具有更好的工作性能和更高的效率,以3%ZnO:8YSZ单电池性能最好。     

实心多孔支撑体全膜化微型固体氧化物燃料电池的制备及性能

提出一种实心多孔支撑体全膜化微型固体氧化物燃料电池(micro solid oxide fuel cell,μSOFC)设计模型.电池用氧化钇部分稳定的氧化锆[(ZrO2)0.97(Y2O3)0.03,partially stabilized zirconia,PSZ]多孔陶瓷作为支撑体,在其上制备NiO-YSZ阳极层,分别采用离心和浸渍两种成膜工艺制备YSZ电解质膜,以La0.8Sr0.2MnO3-YSZ复合材料为阴极,对组装好的单电池进行了电化学性能测试.在850℃和800℃时,离心沉积工艺制备的单电池最大输出功率密度分别为286 mW/cm2和254 mW/cm2,而浸渍涂布法制备单电池的最大输出功率密度则分别达到572 mW/cm2和388 mW/cm2.电化学阻抗谱显示;电极极化是影响电池性能的主要因素.     

应用于大尺寸平板型固体燃料电池电堆的Al2O3-SiO2-CaO基密封材料软化特性及其验证

设计研制了Al₂O₃-SiO₂-CaO基密封材料,对其高温晶化与软化、热性能、界面黏结特性开展了原位观察,并进行了电堆实际应用验证。结果表明:在不高于1 100℃时该密封材料均为非晶态,850℃开始软化,900~1 000℃出现球化。热重分析表明密封材料在0~960℃的质量损失较小,约为0.06%;密封材料与连接板、电池界面黏结紧密,利于固体氧化物燃料电池(SOFC)电堆密封应用。采用研制的密封材料组装了2个5单元SOFC短堆,分别进行了热循环与稳定性研究。结果表明:2个5单元电堆的开路电压达到6.0 V,平均开路电压1.2 V,电堆1热循环前后在35 A(0.56 A/cm²)条件下输出功率为运行无衰减,电堆2在27 A(电流密度0.43 A/cm²)进行恒流放电,运行300 h较为稳定。