Pr_(1.8)La_(0.2)Ni_(0.74)Cu_(0.21)Ga_(0.05)O_(4+δ) as a potential cathode material with CO_2 resistance for intermediate temperature solid oxide fuel cell

摘要

Pr_(1.8)La_(0.2)Ni_(0.74)Cu_(0.21)Ga_(0.05)O_(4+δ) (PLNCG), a mixed ionic electron conductor (MIEC) with a K_2NiF_4-type structure, has been studied as a potential cathode material based on YSZ (ZrO_2 with 8 mol% Y_2O_3) electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs). The X-ray diffraction (XRD) analysis reveals that the good chemical compatibility between the PLNCG and YSZ. The maximum electric conductivity of the PLNCG appeared at about 460 ℃ and the value was 32 S cm~(-1) in air and 34 S cm~(-1) in O_2, respectively. A hollow fiber SOFC was fabricated with the PLNCG as the cathode, NiO-YSZ (1:1; w/w) as the anode and YSZ as the electrolyte. The maximum power density of the cell is 876 mW cm~(-2) and the corresponding polarization resistance of the cell is 0.41 Ω cm~2 at 750 ℃. Furthermore, the PLNCG cathode shows an excellent CO_2 resistance in the operation temperature range. The maximum power density of the cell is similar to that when the cathode is exposed to air. Furthermore, the cell performance is stable when the CO_2 concentrations in the air vary from 0 to 10 vol.% at both 700 and 750 ℃. These results indicate that the PLNCG can be a good candidate for CO_2 resistance cathode materials of IT-SOFCs based on YSZ electrolyte.