Long-term stability of carbon dioxide electrolysis in a large-scale flat-tube solid oxide electrolysis cell based on double-sided air electrodes

Solid oxide electrolysis cell is a highly promising technology for CO₂ electrolysis and has attracted wide attention. But the durability is insufficient by known designed structure of solid oxide electrolysis cell due to structure damage. In this work, a new flat-tube solid oxide electrolysis cell (SOEC) based on double-sided air electrodes with mechanically-strong redox properties and larger active area was proposed and applied to electrolysis of CO₂, and its electrochemical performance and long-term durability were investigated. The results showed that the charging current density reaches −600 mA/cm₂ at 1.5 V and 750 °C under H₂/CO₂ atmosphere. The CO₂ conversion rate achieves 47.4% with energy conversation efficiency of 91.4% at the electrolysis voltage of 1.305 V under the charging current density of −400 mA/cm², corresponding to 210 mL/min of CO production rate. This new cell architecture for CO² electrolysis was stable at the current density of −300 mA/cm² for 1910 h at 750 °C with a degradation rate of 4.89%/kh. The new flat-tube solid oxide electrolysis cell is capable to conduct CO₂ electrolysis with high efficiency and long-term stability.