Microstructure and catalytic activity of Li_0.15Ni_0.25Cu_0.3Zn_0.3O_2-δ-Ce_0.8Sm_0.2O_1.9-carbonate nanocomposite materials functioning as single component fuel cell

The single component fuel cell (SCFC) is a novel physical-electrochemical device for energy conversion which is recently discovered. The functional composite materials of Li_0.15Ni_0.25Cu_0.3Zn_0.3O_2-δ (LNCZO) and Ce_0.8Sm_0.2O_1.9 (SDC)-carbonate are proved as unique materials in SCFC (or one-layer fuel cell). In this work, the microstructure and morphology of two composite materials of LNCZO-SDC-Na₂CO₃ (LNCZO-NSDC) and LNCZO-SDC-(Li/Na)₂CO₃ (LNCZO-LNSDC) are investigated by SEM-EDX and HR-TEM. Their catalytic activities for both hydrogen oxidation and oxygen reduction are studied by H₂-TPR and O₂-TPD, respectively. It is discovered for the first time that binary carbonates as ionic conductor mixing with semiconductor homogenously help to form unique semiconducting-ionic microstructure. The particle arrangement and interface conduction in the microstructure significantly influences on the SCFC performances due to different catalytic activity and polarization resistance. Even this, O₂ reduction reaction (ORR) for the single homogeneous layer still predominates in the redox reaction and binary carbonates are in favor of the oxygen conduction and desorption. These fin dings are essential to exactly understand the connections among structure, catalytic activities and performances underlying SCFC.