Preparation And Sinability Of BZCYYb Powder For Proton Conductor Based Solid Oxide Fuel Cell Electrolyte

Y,Yb co doped barium zirconate barium cerite based electrolyte has excellent ionic conductivity at low temperature and good chemical stability in working atmosphere.However,its poor sintering activity brings challenges to thin film electrolyte.The sintering performance of BZCYYb electrolyte is improved by optimizing the morphology of electrolyte powder and adding a small amount of sintering additives.(1)Prepared high sintering activity BZCYYb electrolyte powder using glycine nitrate combustion method and improved Pechini method.XRD results showed that pure phase can be obtained by calcining at 1000℃ for 5 hours,and compared with commercial BZCYYb powder After BZCYYb holding at 1500℃ for 5 hours,the relative density of the electrolyte was 96.51%,and the conductivity in wet H2 was 2.71×10-2 S/cm at 700 ℃,with a conductivity of 1.27×10-2 S/cm in dry air at 700℃.(2)Using nanoscale and micrometer scale NiO with different additions(2,4,6 mol.%)as sintering aids for BZCYYb electrolyte,the effects of these additives on the phase structure,sintering activity,microstructure,element distribution,and conductivity of BZCYYb electrolyte were investigated.The particle size and dosage of NiO were optimized.All electrolyte samples with sintering additives were kept at 1400℃ for 5 hours,and the relative density was greater than 95%.As the amount of NiO added increased,the density of the electrolyte showed a trend of first increasing and then decreasing.Among them,the BZCYYb electrolyte with 2 mol.%nanoscale NiO added had the highest relative density and conductivity.In wet H2,the conductivity was 1.71 × 10-2 S/cm at 700℃.(3)Li2CO3 was used as a sintering aid for BZCYYb electrolyte,and electrolytes were prepared with 4,8,12,and 16 mol.%additions at 1250,1300,and 1350℃ for 3 hours.The sintering effect of LiCO3 on BZCYYb electrolyte was investigated.The experimental results show that adding an appropriate amount of Li2CO3 can maintain the ion conductivity of BZCYYb while significantly reducing its sintering temperature without changing the crystal form and phase of BZCYYb.The optimal addition amount of Li2CO3 is 8 mol.%.After holding at 1350℃ for 3 hours,the relative density of BZCYYb with 8 mol.%Li2CO3 added is 95.37%.At 700℃,the conductivity is 1.922×10-2 S/cm.