Essential microstructure of cathode functional layers of solid oxide electrolysis cells for CO2 electrolysis

This study has demonstrated the importance of cathode functional layer of solid oxide electrolysis cells for CO2 electrolysis via comparing with that of solid oxide fuel cells and varying microstructure. Reducing inactive CO2 over cathodes dominates CO2 electrolysis performance in solid oxide electrolysis cells while H2 oxidation over Ni-based anodes has less effect on solid oxide fuel cells performance. Two supporting cathodes with different functional layer microstructure are compared. The cathode with dendritic pore structure shows higher performance than that with microchannel structure in terms of gas diffusion and polarization resistance owing to the faster gas diffusion pathway. The dendritic pore structure also prevents particle sintering during densifying electrolyte film. Therefore, the microstructure of cathode functional layer plays an essential role in CO2 electrolysis.