Performance and Stability of La2NiO4+X As Air Electrode of Solid Oxide Electrolysis Cell

Solid oxide electrolysis cell (SOEC) is regarded as one of the most promising hydrogen generation devices. However, electrolysis operated at high temperature has some problems; component inter-diffusion and difficulty in the selection of sealant etc.. SOEC (IT-SOEC) at intermediate temperature (550~650^oC) may reduce problems, however, most of the overpotential occurs in air electrode. In this study, we have tested La₂NiO_4+δ (LNO) as an air electrode and compared the performance with that of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) which shows degradation due to Sr segregation. LNO has advantages due to its good thermal-expansion coefficient (TEC) match with electrolyte and little cation segregation. Electrochemical performance of SOEC at 650^oC under electrolysis current shows that LNO is a promising as an air electrode.