Use of ash-free “Hyper-coal” as a fuel for a direct carbon fuel cell with solid oxide electrolyte

•The feasibility of using Hyper-Coal as the solid fuel in solid oxide fuel cells is proposed.•Ash-free Hyper-Coal is in the plastic/soft stage at temperatures 600–850 °C during DC-SOFC performance.•A peak power density of 120 mW/cm−2 was achieved at 811 °C for a DC-SOFC supplied by Hyper-coal.•Stable current performance was observed for a DC-SOFC under a load ΔE = 0.5 for over 160 h.•Iron seems to be an effective catalyst for improving DC-SOFC performance.

“Hyper-coal”, produced by the Kobe Steel Company, was investigated by analytical and physico-chemical methods to consider its potential usability as a fuel for a direct carbon fuel cell with solid oxide electrolyte (DC-SOFC). The performed tests showed that DC-SOFCs fed with this processed fossil coal were characterized by stable operation with reasonable current and power densities. The performance of the fuel cells can be improved by using iron as a catalyst for the anodic reaction and by the choice of appropriate working conditions.