Efficient syngas generation for electricity storage through carbon gasification assisted solid oxide co-electrolysis

Highlights: • A novel syngas production system is achieved by CG assisted co-electrolysis. • Electricity consumption is significantly reduced with carbon in the anode. • CG assisted co-electrolysis is demonstrated on LSGM-based SOECs. - Abstract: High temperature CO₂ and H₂O co-electrolysis is a promising way to produce syngas for the storage of electrical energy harvested from renewable energy sources. However, a significant portion of electricity input is consumed to overcome a large oxygen potential gradient between the electrodes in conventional solid oxide electrolysis cells (SOECs). In this study, we present a novel and efficient syngas generator integrating carbon gasification and solid oxide co-electrolysis to improve the system efficiency. The feasibility of this new system is demonstrated in La_0.9Sr_0.1Ga_0.8Mg_0.2O₃ (LSGM) electrolyte-supported SOECs. Both thermodynamic calculation and experimental results show that the potential barrier for co-electrolysis can be reduced by about 1 V and the electricity input can be saved by more than 90% upon integration of SOECs with carbon gasification. On the anode side, "CO shuttle" between the electrochemical reaction sites and solid carbon is realized through the Boudouard reaction (C + CO₂ = 2CO). Simultaneous production of CO on the anode side and CO/H₂ on the cathode side generates syngas that can serve as fuel for power generation or feedstock for chemical plants. The integration of carbon gasification and SOECs provides a potential pathway for efficient utilization of electricity, coal/biomass, and CO₂ to store electrical energy, produce clean fuel, and achieve a carbon neutral sustainable energy supply.