溶胶凝胶法制备Ce_(0.8)Y_(0.2-x)Sr_xO_(2-δ)电解质材料及其性能研究

Properties of Ce_(0.8)Y_(0.2-x)Sr_xO_(2-δ) Electrolyte Prepared by Sol-gel Method

采用溶胶-凝胶法制备了固体氧化物燃料电池(SOFCs)电解质材料Ce_(0.8)Y_(0.2-x)Sr_xO_(2-δ)(x=0.00、0.02、0.04、0.06、0.08),并通过红外光谱、热重-差示扫描量热分析、X射线衍射、扫描电镜、交流阻抗等对试样进行分析表征。结果表明,采用溶胶-凝胶法经700℃煅烧所得粉体呈现单相立方萤石结构,平均晶粒尺寸在8 nm^19 nm之间;溶胶-凝胶法制备的Ce_(0.8)Y_(0.2-x)Sr_xO_(2-δ)具有较高的烧结活性,经1400℃烧结2 h后材料的相对密度均大于98%。电化学性能研究显示,Y、Sr双掺杂能提高CeO_2基电解质的电性能,其中Ce_(0.8)Y_(0.16)Sr_(0.04)O_(1.88)在中温条件下具有良好的离子导电率、适中的电导活化能。Ce_(0.8)Y_(0.16)Sr_(0.04)O_(1.8)在800℃时的离子电导率为0.039 S/cm,电导活化能为0.86 eV。

Electrolyte materials Ce（0.8）Y（0.2-x）SrxO（2-δ）（x = 0. 00、0. 02、0. 04、0. 06、0. 08） were synthesized by sol- gel method. The samples were characterized by IR,TG- DSC,XRD,SEM and AC impedance,respectively. XRD shows the crystal structure of the sintered samples to be cubic fluorite structure calcined at 700 ℃ for 2 h. The average grain sizes are between 8 nm and 19 nm. The ultrafine powders of Ce（0.8）Y（0.2-x）SrxO（2-δ）have higher sintering activity and higher relatively dense over 98% after sintered at 1400 ℃ for 2 h. The experimental results show that co- doping can prominently improve electrical properties of electrolyte. Ce（0.8）Y（0.16）Sr（0.04）O（1.88） shows the maximum conductivity,σ800 ℃= 0. 039 S / cm,with the activation energy Ea= 0. 86 eV among all the compositions investigated.