Effect of chemical reactions between electrolyte and lithium compounds on the electrochemical performance of the ceramic fuel cells

Abstract

Previous studies have found that the ceramic fuel cell using Ni0.8Co0.15Al0.05LiO2 (NCAL) symmetrical electrode has obtained very good power generation performance in the temperature range of 450 to 550 ℃. Previous studies have pointed out that after being reduced by H2, NCAL anode will produce LiOH/Li2CO3 mixture and diffuse into the electrolyte, which results in the high ionic conductivity of the cell. In this study, the chemical reactivity of different oxide electrolytes such as CeO2, TiO2, ZrO2 and YSZ with LiOH and/or Li2CO3 and their effects on the electrochemical performance of the cell were studied. It is found that at 550 °C, only the open circuit voltage (OCV) of the cell using CeO2 as electrolyte can remain stable, and the maximum power density (MPD) of the CeO2 electrolyte cell reaches 599.6 mW·cm−2. The OCV of the cells with TiO2, ZrO2 and YSZ as electrolyte increased to the highest value within a few minutes, and the MPD of the cells was only more than 12 mW·cm−2. XRD, FT-IR, SEM-EDS and ICP-OES results indicate that the LiOH/Li2CO3 mixture diffuses into TiO2, ZrO2 and YSZ electrolytes and reacts with three oxides to produce Li2TiO3 and Li2ZrO3, respectively, which results in the low performance of the cell.