SOFC Cathode Prepared from Composite Particles and its Properties

Abstract

The composite particles were prepared by one-step mechanical processing of the starting raw powders of La_0.8Sr_0.2MnO₃ （LSM） and scandia stabilized zirconia （ScSZ） fine particles. In this paper, volume percentage of ScSZ in composite particles was set as 50 vol％ and 62 vol％, respectively. The SOFC cathodes using the composite particles were prepared by sintering at 1200℃. Sintering time was selected as 2h and 3h. As results of electrochemical examinations by AC impedance measurements, the increased content of ScSZ （62 vol％） and the shorter sintering time （2h） contributed to improving the polarization resistance （R_p） of cathodes. Three factors such as conductivity of oxygen ion, formation of triple phase boundaries and gas diffusivity were discussed for the improvement of R_p using the Bode plots which showed the relationship between the absolute value of imaginary part of impedance and the frequency.