Experimental Investigation of the Manufacturing of Porous Solid Oxide Fuel Cells

Abstract

Solid oxide fuel cells (SOFCs) are typically operated in a dual-chamber setup, where the fuel and oxidant flows are separated by the fuel cell. However, dual-chamber SOFCs (DCSOFCs) require sealant to keep the flows separate, meaning that rapid heating and cooling cycling could break the seal. The initial answer to this problem was a single-chamber SOFC (SC-SOFC). The SC-SOFC is simply a planar fuel cell mounted parallel to a mixed fuel and oxidant flow. This system operates through the catalytic reactions of the anode and cathode with the fuel and oxidant, respectively. The drawback of this design comes from the requirement of fuel rich flow. A fuel lean flow leads to the oxidation of the anode and failure of the cell. On the other end, a fuel rich flow will greatly decrease system efficiency as much fuel will pass the cell and be wasted, making SC-SOFCs a difficult technology to implement. This issue led to the development of a porous SOFC (PSOFC), as a variant on the SC-SOFC. The PSOFC incorporates a similar mixed flow but is mounted perpendicular to the flow with cathode upstream of anode, and a catalyst downstream of the anode with the goal of reforming exhaust into syngas for a zero-emission fuel cell. Pores through the entire cell allow the flow to reach the anode, from the cathode side of the cell. The zero-emission condition is realized with the use of hydrocarbon fuels in the mixed flow. Reactions of fuel and air in the cell result in products of CO2 and H2O, which are then reformed by the catalyst into syngas (H2 and CO). Exhaust reformation by the catalyst is possible due to the high operating temperature of SOFCs. Syngas from the cell may be used immediately for further electricity generation or stored for later use. Manufacturing of a PSOFC is carried out with additive manufacturing (3D printing). Techniques of manufacturing PSOFCs will be discussed. The catalyst layer has been omitted from cell production until electricity generation performance of the cell improves. PSOFCs tested thus far have produced under 100 mW/cm2 with an open circuit voltage (OCV) of 0.60 V. This performance is not enough to begin implementing PSOFCs in industry. However, it does set a solid base for future PSOFCs and shows that they are a viable source of power generation. With further improvement of manufacturing methods and implementation of a catalyst, PSOFCs will become an important tool in zero-emission power production.