Carbon gasification from a molten carbonate eutectic

This investigation explores the impact of using a ternary alkali metal carbonate eutectic, i.e., Li₂CO₃, Na₂CO₃, and K₂CO₃ (43.5: 31.5: 25 mol%, respectively), as a catalyst for carbon gasification under CO₂ and non‐CO₂ atmospheres. Gasification under CO₂, i.e., the reverse Boudouard reaction, is a well‐understood process with considerable commercial interest. However, in the context of direct carbon fuel cell (DCFC) operations, it is a parasitic reaction because it consumes fuel without producing power. In this study, the effect on carbon gasification of a common DCFC electrolyte is examined. Thermogravimetric analysis shows gasification occurring in the absence of a CO₂ atmosphere, which has significant implications for DCFCs using alkali metal carbonates as the secondary electrolyte. A combined reaction mechanism is proposed which entails gasification from carbonate and carbonate decomposition.