以化学计量比的SrCO3、C03O4和Tb4O7为原料,采用固相法合成了中温固体氧化物燃料电池阴极材料Sr1-xTbxCoO3-δ(STC,x≤0.3),采用XRD、ND、TGA、范德堡直流四探针法和电化学方法对STC的晶体结构、高温失重、电导率、极化电阻以及电池进行了研究.结果表明:Sr0.9Tb0.1CoO3-δ的晶体结构是立方相Pm-3m空间群结构；Sr0.8Tb0.2CoO3-δ和Sr0.7Tb0.3CoO3-δ是四方相14/mmm结构.在500～800℃时,STC的总电导率(σ)均大于407 S/cm.极化电阻(Rp)和活化能(Ea)随着x的增加而增大.当x=0.1时,STC的氧离子空位浓度最大,具有最好的阴极性能,由其组成的单电池最大功率密度为836 mW/cm2.%Cathode materials consisting of Sr1-χTbχCoO3-δ (STC, χ≤0.3) were prepared by solid-state reaction from stoichiometric proportions of SrCO3, Co3O4 and Tb4O7. Crystal structure, weight loss processes, electronic conductivity, polarization resistance and cell performance were investigated by XRD, ND, TGA, Van Der Pauw DC four-probe method and electrochemical method, respectively. XRD shows the presence of two structural phases in the series belonging to Pm-3m for Sr0.9Tb0.1CoO3-δ and I4/mmm for Sr0.8Tb0.2CoO3-δ and Sr0.7Tb0.3CoO3-δ. Electronic conductivity measurements show that the conductivities of STC were all higher than 407 S/cm in the temperature range of 500℃ to 800℃. AC impedance measurements in symmetrical cells with LSGM as an electrolyte show that the polarization resistance (Rp) and the activation energy (Ea) increase with increasing Tb content. Sr0.9Tb0.1CoO3-δ, with the largest concentration of oxygen vacancies exhibits the best cathode characteristics with maximum power density of 836 mW/cm2.
展开▼
