Performance degradation mechanism of lithium compounds ceramic fuel cell with GDC as electrolyte

The performance degradation mechanism of ceramic fuel cell with NCAL (Ni_0.8Co_0.15Al_0.05LiO₂) as symmetrical electrode and GDC as electrolyte in H₂ is investigated. It is found that under the condition of 550 °C and constant current density of 0.2 A·cm⁻², the output voltage of the cell is about 1.005 V in the initial 10 h and remains relatively stable. After 10 h, the voltage of the cell began to decrease gradually, and by 50 h, the voltage had decreased to 0.522 V. The results testing electrochemical performance of the cell and characterizing the cell materials before and after test using SEM, TOF-SIMS and FTIR indicate that the distribution of Li₂O/LiOH/Li₂CO₃ compounds generated from NCAL anode in the cell plays a vital role in significantly improving the ionic conductivity of electrolyte and gas tightness of the cell. The dynamic migration of molten salt destroyed the continuity of molten salt in the cell, which in turn adversely impacted the ionic conductivity of electrolyte, gas tightness of the cell, and electrochemical reactions on both sides of the cathode and anode. These finally lead to the degradation of the cell performance.