固体氧化物燃料电池新型钙钛矿La0.9Ca0.1Fe0.9Nb0.1O3-δ阳极的制备及其性能研究

doi:10.15541/jim20170016

摘要/Abstract

摘要：

Ni-YSZ作为固体氧化物燃料电池(SOFCs)的传统阳极具有良好的催化性能, 但存在碳沉积、抗氧化还原能力差及硫毒化等问题, 因此钙钛矿型材料以其良好的催化活性及耐H₂S毒化能力而成为研究热点。为此, 本工作开发出了一种新型的Nb掺杂Fe基钙钛矿阳极材料La_0.9Ca_0.1Fe_0.9Nb_0.1O_3-_δ。Fe位引入Nb显著地提高了材料在高温还原气氛中的结构稳定性, 而对材料的热膨胀行为影响很小, 掺杂前后材料的热膨胀系数分别为11.67×10^-6 K^-1和11.57×10^-6 K^-1。掺入Nb提高了阳极材料在还原气氛中的电导率, 该材料在800℃时氢气中的电导率为1.95 S/cm。测试结果表明, La_0.9Ca_0.1Fe_0.9Nb_0.1O_3-_δ阳极在H₂和CO中均表现出优异的放电性能, 在800℃时放电功率分别达到539和491 mW/cm², 电池在CO中放电200 h性能无衰减, 显示出很好的长期稳定性。研究表明La_0.9Ca_0.1Fe_0.9Nb_0.1O_3-_δ是一种极具应用前景的新型钙钛矿阳极材料。

关键词: 固体氧化物燃料电池, 钙钛矿结构, 湿法浸渍, 阳极

Abstract:

The conventional Ni-YSZ anode as a cermet for solid oxide fuel cells (SOFCs) suffers from several shortcomings typically including low resistance to carbon coking, re-oxidation as well as sulfur poisoning. Perovskite anode as a potential substitute for Ni-YSZ anode has drawn much attention due to its impressive merits regarding carbon coking and re-oxidation resistance ability. In this study, a novel Nb-doped Fe-based perovskite anode candidate La_0.9Ca_0.1Fe_0.9Nb_0.1O_3-_δ was developed in which the addition of Nb greatly enhanced the structure stability in reducing atmosphere while the thermal expansion behavior was subtly influenced. The thermal expansion coefficient of the novel Nb-doped Fe-based perovskite anode changed from 11.67×10^-6 K^-1 to 11.57×10^-6 K^-1 after Nb doping while the electrical conductivity was greatly improved as well. At 800℃, the electrical conductivity of the novel Nb-doped Fe-based perovskite anode in H₂ reached up to 1.95 S/cm. The cell with La_0.9Ca_0.1Fe_0.9Nb_0.1O_3-_δ anode prepared by infiltration method presented high electrochemical performance. The maximal power densities in H₂ and CO at 800℃ were up to 539 and 491 mW/cm², respectively. It is remarkable that the cell has impressive long-term stability in pure CO at 800℃ for as long as 200 h. The results indicate that the perovskite La_0.9Ca_0.1Fe_0.9Nb_0.1O_3-_δ material is electrochemically active for both H₂ and CO oxidation which can be taken as a promising anode candidate for SOFCs practical applications.

Key words: SOFCs, perovskite, wet impregnation, anode

中图分类号:

TQ174

赵晓虹, 王勇, 刘立敏, 李斌. 固体氧化物燃料电池新型钙钛矿La_0.9Ca_0.1Fe_0.9Nb_0.1O_3-_δ阳极的制备及其性能研究[J]. 无机材料学报, 2017, 32(11): 1188-1194.

ZHAO Xiao-Hong, WANG Yong, LIU Li-Min, Li Bin. Preparation and Electrochemical Performance of a Novel Perovskite Anode La_0.9Ca_0.1Fe_0.9Nb_0.1O_3-_δ for Solid Oxide Fuel Cells[J]. Journal of Inorganic Materials, 2017, 32(11): 1188-1194.

图/表 7

图1 不同Nb掺杂量的材料分别在850℃空气(a)和氢气(b)中热处理4 h后的XRD图谱

Fig. 1 XRD patterns of the materials doped with different Nb contents after heat-treatment at 850℃ for 4 h in air (a) and H2 (b), respectively

图2 LCF和LCFNb0.1材料在空气中和氢气中的电导率与温度关系图

Fig. 2 Temperature dependence of the electrical conductivity of LCF and LCFNb0.1 in H2 and air, respectively

图3 LCF和LCFNb0.1材料的热膨胀行为

Fig. 3 Linear thermal expansion (ΔL/Lo) of the LCF and LCFNb0.1 rectangular samples measured in stagnant air

图4 LCFNb0.1|ScSZ|LSM/ScSZ电池的SEM照片

Fig. 4 SEM images of the cell with configuration of LCFNb0.1/ScSZ|ScSZ|LSM/ScSZ Cross section of the porous ScSZ layer before (a) and after (b) infiltration along with EDS mapping results; The magnified cross-section of the LCFNb0.1 anode (c) and the magnified surface of the LFCNb0.1 anode (d)

图5 LCFNb0.1|ScSZ|LSM/ScSZ电池在不同温度下不同气氛中的放电曲线

Fig. 5 I-V and I-P curves of the cell with LCFNb0.1 anode at different temperature in different atmosphere

图6 不同温度下LCFNb0.1|ScSZ|LSM/ScSZ电池在H2和CO中的开路阻抗谱

Fig. 6 Electrochemical impedance spectra of the cell with LCFNb0.1 anode under open-circuit in H2 and CO, respectively

图7 在800℃时, LCFNb0.1|ScSZ|LSM/ScSZ电池以CO为燃料时在电流密度为454 mA/cm2时的长期稳定性

Fig. 7 Long-term stability of the cell of LCFNb0.1|ScSZ| LSM/ScSZ at constant current density of 454 mA/cm2 in CO at 800℃

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