Electrochemical performance of yttria-doped SrCoO3_8as cathode material for anode-supported solid oxide fuel cell

摘要

Yttria-doping strategies of strontium cobaltite(SrCoO_(3-δ))have been systematically investigated as high-performance cathode materials for anode-supported solid oxide fuel cells.Sr_(0.95)Y_(0.05)CoO_(3-δ)(SYC),SrCo_(0.95)Y_(0.05)O_(3-δ)(SCY),and Sr_(0.95)Y_(0.05)Co_(0.95)Y_(0.05)O_(3-δ)(SYCY)were prepared by the citrate complexation sol-gel method.The crystal structures,oxygen desorption characterizations,electronic conductivities,and electrochemical performances were studied.The research result suggested that yttria doping into the A-site of SrCoO_(3-δ)(SYC)exhibited the highest electronic conductivity(~580 S cm~(-1)),and the suppression of the oxygen vacancies results in the poor performance of oxygen reduction reaction(ORR)activity.The yttria doping into the B-site of SrCoO_(3-δ)(SCY)inhibits the oxygen desorption related to the Co~(3+)to Co~(2+)and electronic conductivity.The co-doping yttria of SrCoO_(3-δ)(SYCY)shows the lowest area-specific resistances(0.147 Ω cm~2at 600℃)and lowest activation energy(103.8 KJ mol~(-1)).The ORR processes of SYC,SCY,and SYCY electrodes were analyzed by the distribution of relaxation time(DRT)technique.The I-V and I-P performances of SYCY cathode based on the anode-supported single fuel cell were also being exploited,and the peak power density of this cell is 1005 mW cm~(-2)at 650° C.The encouraging results suggest that SYCY is a candidate reduction electrode for solid oxide fuel cell.