Direct Linz-Donawitz converter gas fueled solid oxide fuel cells

This study investigates the feasibility of Linz-Donawitz converter gas (LDG), a by-product from steel manufacturing, as a direct fuel for solid oxide fuel cells (SOFCs). Due to its high CO content, LDG poses challenges such as carbon deposition and sluggish electrochemical kinetics. To address these issues, Ni-GDC anodes were fabricated and modified via Pd infiltration. Carbon accumulation under varying CO/CO₂ and LDG conditions was analyzed, revealing effective suppression above 800 °C, particularly under LDG due to fuel dilution. Electrochemical characterization revealed that the hydrogen and nitrogen in LDG alleviated polarization resistance compared to that in pure CO/CO₂ mixtures. Pd infiltration further reduced resistance by enhancing surface kinetics and charge transfer, as confirmed by distribution of relaxation time (DRT) analysis. The single cell employing a Pd-infiltrated Ni-GDC anode exhibited a maximum power density of 990 mW cm⁻² at 800 °C under dry LDG, a 39.4 % improvement over the non-infiltrated cell. Meanwhile, Long-term operation with humidified LDG (3 vol% H₂O) stabilized performance for over 100 h with minimal voltage degradation (∼0.3 mV h⁻¹). These results demonstrate the potential of direct LDG utilization in SOFCs without external reforming, contributing to greenhouse gas reduction and energy valorization in the steel industry.