Enhancement of the electrochemical properties for La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ oxygen electrode by the addition of Ca_xCo₄O_9+δ nano-catalysts

La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF) perovskite with good stability and high oxygen diffusion coefficient has been extensively studied as oxygen electrode in reversible solid oxide cells (RSOCs). Significant promotion of oxygen reaction kinetics of the LSCF oxygen electrode was achieved by the addition of Ca_xCo₄O_9+δ (CCOx, x = 3, 1.5) nano-catalysts in the present study. The La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ-Ca_1.5Co₄O_9+δ (LSCF-CCO1.5) electrode exhibited the optimal electrochemical property among the LSCF-based electrodes and the lowest polarization resistance (R_p) of 0.039 Ω·cm² was attained at 800 °C, which was ~ 97% lower than that of the LSFM electrode. Furthermore, the LSCF-CCO1.5 oxygen electrode also manifested excellent thermal cycling stability and alternating polarization durability. The hydrogen production rate of the LSCF-CCO1.5 electrolytic cell was 946 mL·cm⁻²·h⁻¹ at 1.5 V at 800 °C, which was 2.6 times higher than that of the LSCF cell (362 mL·cm⁻²·h⁻¹). The results certified the enhancement of electrochemical properties for LSCF oxygen electrode by the addition of CCOx nano-catalysts.