Effects of different lithium compound electrodes on the electrochemical performance of the ceramic fuel cells

The effects of five different lithium compound electrodes LiNi_0.83Co_0.11Mn_0.06O₂ (LNCM-811), LiNi_0.6Co_0.2Mn_0.2O₂ (LNCM-622), LiNi_0.5Co_0.2Mn_0.3O₂ (LNCM-523), LiMO₄ (LMO) and LiCO₂ (LCO) on the electrochemical performance of the ceramic fuel cells with GDC as the electrolyte were investigated. It is found that the maximum power density (MPD) of the cell with LNCM-811 as the symmetrical electrode is the highest in H₂ at 550 °C among the five cells with different electrodes. The ionic conductivity of the composite electrolyte formed during performance testing in the cell with LNCM-811 as electrode is also the highest. With the decrease of Ni content in LNCM, the MPD of the cells with LNCM as electrode gradually decreases. The MPD of the cell with LCO as electrode was 196.9 mW⋅cm⁻², and MPD of the cell with LMO as electrode was the lowest, only 4.24 mW⋅cm⁻². According to the characterization results of SEM, FTIR and XPS of the different lithium compound electrode materials and the cells before and after performance test, it was found that the change law of the amount of molten salts such as LiOH produced by the reduction of lithium compound in H₂ is consistent with the change law of the MPD of the cells. It is proved that in addition to providing enough catalysts such as Ni and Co that can catalyze the electrode reaction, the key to the outstanding power generation performance of the cell is to produce a sufficient amount of lithium compound molten salt after being reduced in H₂.