A performance study of hybrid direct carbon fuel cells: Impact of anode microstructure

• Effect of anode surface area and pore volume on hybrid direct carbon fuel cells.
• The anode microstructure is modified using poly(methyl methacrylate) pore-formers.
• Fuel cells operate via direct carbon, CO32–-mediated, and CO oxidation reactions.
• The anode surface area plays a dominant role in improving cell performance.
• The improved performance is mainly due to an enlarged active zone for CO oxidation.

Direct carbon fuel cells (DCFCs) have recently attracted great interest because they could provide a considerably more efficient means of power generation in comparison with conventional coal-fired power plants. Among various types of DCFCs under development, a hybrid system offers the combined advantages of solid oxide and molten carbonate electrolytes; however, there is a significant technical challenge in terms of power capability. Here, we report an experimental study demonstrating how anode microstructure influences the power-generating characteristics of hybrid DCFCs. The anode microstructure (pore volume and surface area) is modified by using poly(methyl methacrylate) (PMMA) pore-formers. Polarization studies indicate that cell performance is strongly dependent on the anode surface area rather than on the pore volume. The incorporation of PMMA-derived pores into the anode leads to improved power capability at typical operating temperatures, which is attributed to an enlarged active zone for electrochemical CO oxidation.