Characteristics of Li2CO3 as sintering aid for Ce0.8Sm0.2O2-δ electrolyte in solid oxide fuel cells

Owing to its excellent ionic conductivity, 20 mol% samarium doped ceria (Ce0.8Sm0.2O2-delta, SDC) is considered a promising alternative as an electrolyte in solid oxide fuel cells (SOFCs). SDC electrolytes, however, require high sintering temperatures over 1,600 degrees C to attain sufficient density to be SOFC electrolytes. To lower the SDC sintering temperature, different amounts of Li2CO3 (0-12 mol% of Li) were evaluated as a sintering aid for SDC electrolytes. The SDC electrolyte samples with Li were sintered at 1,400 degrees C and were compared with SDC electrolytes sintered at 1,600 degrees C. The SDC electrolyte with 6 mol% of Li sintered at 1,400 degrees C (Li6SDC1400) was densified to 97.495% of theoretical density (T.D.), which is similar to that achieved by the SDC electrolyte sintered at 1,600 degrees C (97.433% of T.D.). The improved formation of grain boundary in the Li6SDC1400 sample increased the density of the SDC, resulting in enhancement of ionic conductivity and cell performance. At 800 degrees C, the maximum power density of the Li6SDC1400 electrolyte sample was 120.15 mW/cm(2).

Automated summary

20 mol% samarium doped ceria (Ce0.8Sm0.2O2-delta, SDC) shows excellent ionic conductivity in solid oxide fuel cells (SOFCs), but requires high sintering temperatures. Adding Li2CO3 as a sintering aid can lower the sintering temperature and improve cell performance.