Doping strategy on improving the overall cathodic performance of double perovskite LnBaCo_(2)O_(5+σ)(Ln=Pr,Gd)as potential SOFC cathode materials  

作　　者：Fangze Chen Dacheng Zhou Xueqing Xiong Juntao Pan Donglin Cai Ze Wei Xiyong Chen Yihui Liu Nengneng Luo Jialin Yan Toyohisa Fujita 

机构地区：[1]State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures,Guangxi University,Nanning,530004,Guangxi,China [2]School of Resources,Environment and Materials,Guangxi University,Nanning,530004,Guangxi,China [3]Hubei Key Laboratory of Advanced Technology for Automotive Components&Hubei Collaborative Innovation Center for Automotive Components Technology,Wuhan University of Technology,Wuhan,430070,Hubei,China

出　　处：《Journal of Materiomics》2023年第5期825-837,共13页无机材料学学报（英文）

基　　金：supported by the National Natural Science Foundation of China(Grant No.52062002 and 51961006);the Open Foundation of Guangxi Key Laboratory of Processing for Nonferrous Metals and Featured Materials,Guangxi University,China(2021GXYSOF01).

摘　　要：A series of single-phase double perovskite Pr1-xGdxBaCo_(2)-yFeyO_(5+σ)(x=0,0.5 and 1,0≤y≤1)materials were engineered through A/B site co-doping strategy to improve the mechanical,electrical and electrochemical properties as potential cathode materials for the application of intermediate solid oxide fuel cells(IT-SOFCs).The corresponding thermochemical stability,thermal expansion behavior,electrical conductivity and cathodic polarization resistance of the materials were systematically investigated.It was found that the A-site dual lanthanide doped Pr_(0.5)Gd_(0.5)BaCo_(2)O_(5+σ)(PGBCO)exhibits improved electrical conductivity,reduced thermal expansion,and comparatively low electrochemical polarization resistance versus single lanthanide double perovskite,PrBaCo_(2)O_(5+σ)(PBCO)and GdBaCo_(2)O_(5+σ)(GBCO)materials.Further investigation on the effect of B-site Fe-doping on Pr_(0.5)Gd_(0.5)BaCo_(2)-yFeyO_(5)+σ(PGBCF-y,0≤y≤1)reveals that all the PGBCF-y compositions exhibit excellent chemical stability with Gd-doped ceria(GDC)at operating temperatures not higher than 1100℃.Besides,doping of Fe in B-site can effectively reduce the thermal expansion coefficients(TECs)of the Pr_(0.5)Gd_(0.5)BaCo_(2)O_(5)+σceramics at 30e1000℃.And the electrochemical impedance spectra(EIS)results show that the PGBCF-y|GDC|PGBCF-y symmetric cells have acceptable low area specific polarization resistances.Further examination of the cathodic polarization and characteristic capacitance from the AC impedance spectra by employing the relaxation time distribution(DRT)method demonstrated that charge transfer is the dominating subprocess for the oxygen transport through the materials.

关 键 词：Double perovskite Electrical conductivity Thermal expansion Electrochemical polarization Thermochemical stability 

分 类 号：TM911.4[电气工程—电力电子与电力传动]