New insights into single-step fabrication of finger-like anode/electrolyte for high-performance direct carbon solid oxide fuel cells: Experimental and simulation studies

Cell preparation techniques and design parameters have significant impacts on the electrochemical performance of direct carbon solid oxide fuel cells (DC-SOFCs). In this work, a finger-like nickel-based anode/electrolyte has been successfully fabricated in a single step via the tape-casting combined phase-inversion and co-sintering technique, which simplified the preparation process and reduced the fabrication cost. The finger-like anode/electrolyte exhibited identical microstructure and exceptional adhesion, ensuring the absence of any cracks during the co-sintering process. As a result, the corresponding single cell delivered a very competitive output of 436 mW cm⁻² at 850 °C using activated carbon as fuel. Moreover, it operated stably for 20.1 h under 100 mA with a high fuel utilization of 22.5% at 850 °C. Model verification was also performed by comparative analysis of the effects of the finger-like pore length, anode thickness, cathode thickness, and electrolyte thickness on the cell performance using numerical simulation, which generated the resultant two-dimensional distributions of CO molar concentration, current density, O₂ molar concentration, and temperature as well as the power output of the cell. Simulation results verified the experimental findings that DC-SOFC performance was enhanced with increases in the finger-like pore length and cathode thickness, and with decreases in the anode and electrolyte thicknesses. This work provides valuable insights into further optimizing the cell design and manufacturing process, paving the way for the development of high-performance DC-SOFCs.