Microextrusion printing for increasing electrode–electrolyte interface in anode-supported solid oxide fuel cells

Abstract

Microextrusion printing is employed for increasing the interfacial area between the electrode and electrolyte of anode-supported solid oxide fuel cells (SOFCs) to enhance their electrochemical performance. A homogeneous anode paste is prepared as an extrusion material and its rheological properties are measured. Then, the printing resolution (line width of the printed paste) is evaluated by extruding the paste under various printing conditions to determine the appropriate stage speed and flow rate for cell fabrication. A mathematical model is also developed to predict the printing resolution from the printing parameters, and the experimental data of the line width agree well with the predicted values, particularly when the contact angle between the paste and substrate is considered. By varying a paste coverage area, two types of anode-supported SOFCs having different interfacial area enlargement ratios are prepared by extruding the anode paste onto the flat anode substrates. The electrochemical performance of the cell is improved by increasing the interfacial area; the current density at the terminal voltage of 0.7 V at 600 °C is 0.17 A cm−2 in a flat cell, whereas 0.32 A cm−2 in a patterned cell whose enlargement factor is 1.14 compared with that of the flat cell.