A self-recovering robust electrode for highly efficient CO2 electrolysis in symmetrical solid oxide electrolysis cells

Abstract

Symmetrical solid oxide electrolysis cells (S-SOECs) have received increasing attention due to their low fabrication cost and simple preparation procedure. However, the investigation of S-SOECs for CO₂ electrolysis has been hindered due to the lack of high performance stable electrodes with good CO₂ reduction reaction (CO₂-RR) and oxygen evolution reaction (OER) catalytic activity. Herein, a novel perovskite La_0.6Ca_0.4Fe_0.8Ni_0.2O_3−δ (LCaFN) is investigated as an electrode of S-SOECs for CO₂ electrolysis. The S-SOEC has a low polarization resistance of only 0.04 Ω cm² and achieves a maximum electrolysis current density of 1.41 A cm⁻² at 800 °C with pure CO₂ at 2.0 V. LCaFN electrodes show good stability and can be recovered by simple air treatment after a period of operation to avoid the formation of carbonates with alkaline earth elements in the perovskite as La_0.6Sr_0.4Fe_0.8Ni_0.2O_3−δ (LSrFN). The mechanism of self-recovery of the LCaFN electrode by air treatment is discussed and analyzed.