燃料对甘氨酸-硝酸盐法合成Gd_(0.8)Sr_(0.2)CoO_(3-δ)阴极材料的影响

Effect of Fuel Amount on Synthesis of Gd_(0.8)Sr_(0.2)CoO_(3-δ) Cathode Material by Gly-cine-nitrate Process

采用甘氨酸-硝酸盐法（GNP）制备Gd0.8Sr0.2CoO3-δ（GSC）纳米粉体。通过元素化学计量、热力学计算及XRD、SEM、交流阻抗谱等测试手段,研究了甘氨酸与金属离子摩尔比（G/M=1.5、2.0、2.5、3.0、3.5）以及煅烧温度等制备参数对GSC粉料合成反应及电极性能的影响。实验测得凝胶自燃烧时火焰温度在850-1150℃之间,其中G/M=2.5时火焰温度最高,燃烧最完全,与理想化学计量（φ=1）的计算结果相一致,由此制得的粉料呈蓬松泡沫状,粒径细小。交流阻抗谱测试结果表明：1100℃煅烧制得的GSC-2.5阴极与Sm0.2Ce0.8O1.9（SDC）电解质间的界面电阻（ASR）最小,仅0.119.cm2。Gd0.8Sr0.2CoO3-δ电极电导率在500~800℃测试范围内均大于100 S/cm,满足IT-SOFC阴极材料的要求。

Gd_（0.8）Sr_（0.2）CoO_（3-δ） （GSC） nano-powders as cathode materials were synthesized by glycine-nitrate process （GNP） with different glycine-to-metal ratios （G/M=1.5, 2.0, 2.5, 3.0, 3.5）. The performance of GSC cathode calcined at different temperatures was characterized by XRD, SEM and AC impedance spectra. The actual flame temperatures of combustion measured ranging from 850℃ to 1150℃. The flame temperature for the sample of G/M 2.5 is the highest because of the most sufficient combustion which is in agreement with the calculation result of the ideal stoichiometric ratio （φ=1）. Meanwhile, the fluffy foamy powder is obtained with fine grain size. Analysis of the AC impedance spectra shows that the area specific resistance （ASR） between GSC-2.5 cathode prepared at 1100℃ and Sm0.2Ce0.8O1.9 （SDC） electrolyte is mere 0.119 Ω.cm2. The electrical conductivity value of Gd0.8Sr0.2CoO3-δ cathode is higher than 100 S/cm in the temperature range from 500℃ to 800℃, which implies that GSC could be a promising cathode material for IT-SOFC.