Ca、Ba掺杂Sm0.5Sr0.5CoO3作为中低温固体氧化物燃料电池阴极的结构与性能

通过X射线衍射(XRD)、热重、热膨胀、电导率以及电化学交流阻抗等测试技术研究了SmSr1-xAexCo2O6(x=0, 0.2, 0.4, 0.6, 0.8, 1; Ae=Ca, Ba)作为中低温固体氧化物燃料电池(IT-SOFC)阴极的结构与性能. 研究表明, 固相法合成的SmSr0.8Ae0.2Co2O6(Ae=Ca, Sr, Ba; 简写为SSAC)随着Ca、Ba掺杂量的增大晶体结构发生变化. 其中, 空间群为Pnma晶体结构的电极SSAC中, 晶胞参数随着Sr、Ca、Ba的顺序增大; SSAC晶体中的氧空位浓度随着Ca、Sr、Ba的顺序增大, SSAC热膨胀系数与Ae元素关系不大, 氧催化性能随着Ca、Sr、Ba的顺序降低. 由于载流子浓度降低, 使得Ba 掺杂Sm0.5Sr0.5CoO3(SSC)后电极的电导率降低. 由于导电活化能增大, 使得Ca掺杂SSC后电极的电导率也降低.     

以甲醇为燃料的中温固体氧化物燃料电池性能研究

制备了阳极负载型LDC-LSGM双层电解质薄膜电池.考察了单电池在分别使用甲醇和氢气两种燃料时,不同温度下的I～V性能.以甲醇为燃料,以空气为氧化剂时,800℃下的最大输出功率密度为1.07W/cm²,而使用氢气为燃料时,最大输出功率密度为1.54W/cm².通过交流阻抗研究了造成甲醇性能降低的可能原因.结果表明,以甲醇作为燃料时,单电池性能较氢气作为燃料时低.     

Synthesis and electrical properties of Ln<Subscript>2</Subscript>CuO<Subscript>4+</Subscript><Subscript><Emphasis Type="Italic">δ</Emphasis></Subscript> (Ln: Nd or La) mixed conductor sputter deposited coatings

Nd₂CuO₄ and La₂CuO₄ are potential candidates as cathode material for intermediate temperature-solid oxide fuel cells. Nd–Cu and La–Cu oxides were co-sputtered on rotating substrates from metallic La, Nd and Cu targets in the presence of a reactive argon–oxygen gas mixture. Structural and chemical features of these films have been determined by X-ray diffraction and energy-dispersive spectroscopy. Their electrical resistivity was measured using the four-point probe method. As-deposited Nd–Cu based coatings are amorphous and, after annealing, crystallise in K₂NiF_{4+ δ} -type structure for Nd/Cu atomic ratio of 2, with more or less Nd₂O₃ or CuO, depending on whether Nd or Cu is in excess, respectively. As-deposited La–Cu based coatings are also amorphous and crystallise in La₂CuO₄ for La/Cu >2 or in LaCuO_3±δ perovskite-type structure when Cu is in excess. The electrical measurements show a clear relation between resistivity and structure of the coatings. After annealing, crystallised neodymium-based coatings show higher resistivity than lanthanum-based ones. Finally, LaCuO_3±δ exhibit higher resistivity than La₂CuO₄. Paper presented at the 11th EuroConference on the Science and Technology of Ionics, Batz-sur-Mer, Sept. 9–15, 2007.     

复合连接材料LCC/SDC的制备及低温烧结研究

采用微波辅助配合物燃烧法分别制备了La_0.8Ca_0.2CrO_3-δ(LCC)与Sm_0.2Ce_0.8O_2-δ(SDC)两种原料,并按设定比例将两种粉体混合以制备复合连接材料。用X射线衍射(XRD)分别对粉体和烧结体的物相进行分析,用Archimedes排水法测量体积密度并计算烧结品的相对密度,采用扫描电镜(SEM)对烧结体的微观结构进行表征,采用四端探针法测量电导率,用热膨胀仪     

天然气中温SOFC阳极材料铒掺杂的氧化铈的制备与性能研究

采用溶胶-凝胶法合成了新型中温固体氧化物燃料电池(IT-SOFC)阳极材料Ce_1-xEr_xO_y(x=0.00,0.10,0.15,0.20,0.25,0.30)(EDC),并采用共压-共烧结法制备了以NiO-EDC复合阳极为支撑、以Ce_0.8Gd_0.2O_2-δ(GDC)为电解质、以La_0.8Sr_0.2Co_0.8Fe_0.2O_3-δ(LSCF)-GDC为复合阴极的单电池。利用XRD和SEM等方法对阳极材料EDC进行了晶相结构、微观形貌和化学相容性等分析。在400~700 ℃范围内,以加湿天然气(3% H₂O)为燃料气,氧气为氧化气测试了电池的电化学性能。结果表明：EDC阳极材料具有良好的孔道结构;11种不同阳极组成的单电池中50%(质量分数)NiO-50%(质量分数)Ce_0.85Er_0.15O_y(E15C85)阳极支撑的单电池具有最佳的电化学性能,在650 ℃时其最大电流密度为117.84 mA·cm^-2和最大比功率为24.37 mW·cm^-2。     

Auto-combustion synthesis and properties of Ce0.85Gd0.15O1.925 for intermediate temperature solid oxide fuel cells electrolyte

A typical composition of the system Ce_1 − xGd_xO_2 − δ with x = 0.15 (CGO15) has been synthesized by auto-combustion method. DTA/TGA of the precursor compound indicated the completion of reaction at about 270 °C. Greater than 95% of the theoretical density has been achieved by sintering at 1300 °C for 10 h. Single phase formation in as-burnt stage has been confirmed by its powder X-ray diffraction (XRD) pattern. The structural morphology was studied employing bright field transmission electron micrograph (BFTEM) and high resolution transmission electron micrograph (HRTEM). BFTEM image indicates that particles are highly agglomerated and appear to be dispersed in amorphous matrix. Also BFTEM image reveals that the average particle size is 26 ± 5 nm. The presence of amorphous phase in as-prepared ash was also confirmed by HRTEM and selected area diffraction (SAD). The scanning electron micrograph (SEM) of the thermally etched system shows grains having an average size of 400 nm. Impedance measurements have been made in the frequency range 1 Hz to 1.3 MHz between 200 and 500 °C and the total conductivity was measured. An enhanced conductivity value is observed which may make this system suitable for application as a solid electrolyte material for intermediate temperature solid oxide fuel cells (IT-SOFCs).     

中温天然气燃料电池复合阳极NiO-La0.75Sr0.25Cr0.5Mn0.5O3-δ-Ce0.8Sm0.2O2-δ的制备和性能研究

采用共压-共烧结的方法制备了以NiO-La_0.75Sr_0.25Cr_0.5Mn_0.5O_3-δ-Ce_0.8Sm_0.2O_2-δ复合阳极为支撑、以Ce_0.8Gd_0.2O_2-δ(GDC)为电解质、以La_0.8Sr_0.2Co_0.8Fe_0.2O_3-δ(LSCF)-Ce_0.8Gd_0.2O_2-δ(GDC)为复合阴极的单电池,在400～700 ℃范围内,以加湿天然气(3% H₂O)为燃料气,氧气为氧化气,测试了电池的放电性能。利用XRD、SEM、EDX等手段对复合阳极进行结构、化学相容性、微观型貌和碳元素分析。分析结果表明,符合阳极具有较好的化学相容性,且阳极和阴极具有较好的孔隙、孔道结构。EDX测试结果表明有少量的碳沉积。在600 ℃进行了电池的稳定性测试。测试结果表明,该电池在13 h的测试过程中功率无明显衰减,具有较好的稳定性。复合阳极单电池在600 ℃得到最大电流密度,为215.49 mA·cm^-2;最大功率流密度为44.85 mW·cm^-2。     

(Pr0.9La0.1)2(Ni0.74Cu0.21Ga0.05)O4+δ纳米纤维阴极的制备及电化学性质

采用静电纺丝法制备了(Pr_(0.9)La_(0.1))_2(Ni_(0.74)Cu_(0.21)Ga_(0.05))O_(4+δ)(PLNCG)氧化物纳米纤维。利用热重-差热分析(TG-DTA)、X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)和扫描电子显微镜(SEM)对材料的物相及微观形貌进行分析。研究表明950℃煅烧5 h得到平均直径420 nm、形貌均一的PLNCG氧化物纤维;1 000℃烧结2 h得到紧密附着在Ce_(0.9)Gd_(0.1)O_(2-δ)(CGO)电解质上的网状结构纤维阴极。电化学阻抗谱(EIS)测试结果表明纳米纤维阴极具有比粉体阴极更优越的性能。700℃的极化电阻(RP)为0.134Ω·cm~2,比同组分的粉末阴极减少32%(RP=0.197Ω·cm~2)。以纤维阴极构筑的电解质支撑单电池Ni-CGO/CGO/PLNCG在700℃的最大输出功率密度为231 m W·cm-2。氧分压测试结果表明阴极反应的速率控制步骤为电荷转移过程。     

镓酸镧基中温-SOFC的新型阳极NiO-La0.3Ce0.7O2-δ研究

采用共沉淀法制备了NiO-La0.3Ce0.7O2-δ(LDC30)新型阳极材料, 通过对其配方与性能的研究, 探索获得中温SOFC高性能阳极材料的新途径.     

Ba1-xPrxCoO3阴极材料在中温SOFC中的应用

采用湿化学法合成系列阴极材料Ba1-xPrxCoO3(x=0.3, 0.4, 0.5, 0.6). TG-DTA和烧结曲线测试结果表明, 在950 ℃时样品发生相变, 形成了晶相. 样品的SEM结果显示, Pr离子掺杂到一定量时, 将抑制晶粒长大, 减少阴极的孔洞率. 单电池测量结果表明, 用x=0.5的阴极材料制成的单电池表现出最好的输出特性, 具有最大短路电流密度和最大输出功率密度, 是掺杂Y的BaCeO3基电解质的一种优化配比阴极材料.