Utilization of mesocarp fiber and the impact of its physicochemical properties on the performance of direct carbon fuel cells

Direct carbon fuel cell (DCFC) is a promising technology for power generation. It works on the utilization of solid carbon fuel and is high in efficiency with low emissions. In this study, biochar derived from oil palm mesocarp fibre (PMF) biomass was evaluated as a fuel supply in a DCFC based on solid-oxide electrolyte. To understand the connection between the physicochemical properties and electrochemical performance of PMF biochar (carbon fuel) in DCFCs better, the PMF biomass is subjected to acid and alkali pre-treatment for structural modification. All samples are characterized by means of thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) and scanning electron microscope (SEM) tests to obtain the link between cell performance and fuel characteristics. The maximum power density of pre-treated PMF biochars reached up to 40-55% level when compared to conventional fuels. In specific, the HCl-treated PMF biochar showed the highest electrochemical reactivity in the DCFC, giving a maximum power output of 11.8 mW cm^-2 at 850 °C. It is found that after pre-treatment, the thermal stability of the biochar increases along with an increase in the surface area and pore volumes. Henceforth, these factors are believed to have a pronounced impact on the electrochemical reaction in the DCFC.