Ca-doped La0.75Sr0.25Cr0.5Mn0.5O3 cathode with enhanced CO2 electrocatalytic performance for high-temperature solid oxide electrolysis cells

Electrolysis of CO2 into CO by using solid oxide electrolysis cells (SOECs) is an advanced and sustainable energy conversion technology in the production of chemical energy by electrical power. However, the development of SOECs is limited because of the lack of cathode with high activity and stability. Herein, La0.75Sr0.25-xCaxCr0.5Mn0.5O3/Gd0.1Ce0.9O2-δ (Cax-LSCM/GDC, x = 0, 0.05, 0.1 and 0.15) composites were obtained by introducing Ca into the A-site of LSCM and developed as desirable cathodes for high-temperature electrolysis of CO2. The electrode polarization resistance (Rp) for CO2 electrochemistry reduction of the half-cell with the Ca0.05-LSCM/GDC cathode shows the minimal values within different temperature and voltage ranges, this cathode has a Rp value of 0.98 Ω cm2 at 800 °C under an applied voltage of 1.0 V, which is decreased by 32% compared with that of the LSCM/GDC cathode under the same test condition. The current density of the full cell with the configuration of Ca0.05-LSCM/GDC|ScSZ|LSM/GDC achieves 31% increase at 1.2 V and 800 °C compared with that of LSCM/GDC cell. Moreover, Ca0.05-LSCM full cell remains fairly stable after 100 h of continuous operation in pure CO2 atmosphere. Results indicate that Ca doped LSCM may be a reliable cathode material for CO2 electrolysis in SOECs.