Investigation of chemical and electrochemical reactions mechanisms in a direct carbon fuel cell using olive wood charcoal as sustainable fuel

• DCFC fueled by olive wood charcoal was tested and cell performance was proved.
• Thermochemical decomposition mechanisms of carbon–oxygen groups were analyzed.
• Complex chain gasification reactions of ligno-cellulosic fuel were confirmed.
• CO/H2/CH4 oxidation was proved at the olive wood charcoal/carbonate anode mixture.
• OCV is independent of temperature and Boudouard reaction is ignored until 700 °C.

Direct carbon fuel cell (DCFC) is a high temperature fuel cell using solid carbon as fuel. The use of environmentally friendly carbon material constitutes a promising option for the DCFC future. In this context, this paper focuses on the use of biomass-derived charcoal renewable fuel. A practical investigation of Tunisian olive wood charcoal (OW-C) in planar DCFCs is conducted and good power density (105 mW cm−2) and higher current density (550 mA cm−2) are obtained at 700 °C. Analytical and predictive techniques are performed to explore the relationships between fuel properties and DCFC chemical and electrochemical mechanisms. High carbon content, carbon–oxygen groups and disordered structure, are the key parameters allowing the achieved good performance. Relatively complex chain reactions are predicted to explain the gas evolution within the anode. CO, H2 and CH4 participation in the anodic reaction is proved.