SOFC纳米La_(0.6)Sr_(0.4)Co_(0.4)Fe_(0.6)O_3阴极粉体的制备及性能表征

Preparation and Characterization of La_(0.6)Sr_(0.4)Co_(0.4)Fe_(0.6)O_3 Cathode Nano-powders for Solid Oxide Fuel Cell

采用EDTA-柠檬酸复合络合法合成了固体氧化物燃料电池(SOFC)纳米阴极粉体La0.6Sr0.4Co0.4Fe0.6O3(LSCF)。运用TG-DTA、FT-IR、XRD、SEM、TEM和电化学分析仪分别对产物形成过程、晶体结构、粉体形貌和电化学性能进行了分析与表征。实验结果表明:在溶胶-凝胶法制备过程中,采用EDTA和柠檬酸同时作为络合剂进行络合反应所制备的凝胶,能在较低的温度(600℃)下生成按化学计量配比的钙钛矿晶体La0.6Sr0.4Co0.4Fe0.6O3,800℃下煅烧的粉体粒子仅为20～30nm,粒子大小较一致,团聚体较少,呈球形。进一步测试其电化学性能,采用该粉体制备阴极的阳极支撑型SOFC纽扣电池(GDC+Ni GDC LSCF)具有较高的性能,以氢气为燃料,空气为氧化剂,在700℃、750℃工作温度下,最大功率密度分别为0.72 W cm-2,0.85 W cm-2,与相同条件下采用柠檬酸单一络合法制备的LSCF粉体相比,电性能有明显提高,其最大功率在700℃、750℃下分别只有0.22 W cm-2、0.46 W cm-2。

Lao.6Sro.4COo.4Feo.603 cathode nano-powders for SOFC were prepared by EDTA-citrate compound complexation method. The gel forming process, crystal structure, the morphology of powders and the electrochemical performance were characterized by TG-DTA, FT-IR, XRD, SEM, TEM and electrochemical workstation. The results revealed that the gel prepared by EDTA-citrate compound complexation method could be synthesized perovskite- type crystal and stoichiometry complex oxides of La0.6Sr0.aCO0.4Fe0.603 calcined at lower temperature （600 ） for 2hrs. This LSCF powders sintered at 800 ℃was with the particle size range only from 20- 30 nm and its shape appears spherical, less aggregate. The electrochemical performance of the SOFC button cell （GDC＋NilGDCILSCF） prepared via LSCF as cathode powders was measured by electrochemical workstation. The maximum power density of the ceil was 0.72 w＂ cm-z and 0.85w＇cm-2 at 700 ℃ and 750 ℃working temperature respectively, in comparison, the maximum power density of the button cell prepared via LSCF as cathode powders, which synthesized via citrate single complexation method, was lower property of 0.22 w＂ cm-2 and 0.46 w＂ cm-2 at 700 ℃ and 750 ℃ operating temperature respectively.