Preparation And Performance Of SOFC Based On ScSZ Electrolyte

Low-temperature solid oxide fuel cells (IT-SOFC) is a promising research direction forthe SOFC. The key to the development of IT-SOFC is to improve the ionic conductivity ofthe electrolyte materials and introduce low-temperature electrode materials, which canreduce the resistance of the electrolyte membrane. There are two ways solving this problem.First of which is developing electrolyte with high ionic conductivity under low operatingtemperatures, such as ScSZ (scandium oxide-stabilized zirconia) and perovskite electrolyte,and another is a thin film electrolyte synthesized with tape-casting and deposition method.Studies have reported that the electrode materials with perovskite (ABO3) structure havehigh oxygen reduction activities and conductivity, which thus attracted tremendous concernin SOFCs. Sr2Fe1.5Mo0.5O6-δ(SFM) with perovskite structure, has been considered as a verypromising anode and cathode material for IT-SOFCs because of its high electricalconductivity and electrochemical catalytic activity. At the same time, altering at A-site orB-site of the ABO3materials can influence the electrode performance.In this paper, ScSZ electrolyte with large-size and anode-supported substrate forimpregnating was synthesized using the tape-casting method, while SFM anode materialwas impregnated into the substrate. A-site deficient SrxFe1.5Mo0.5O6-δ(x=1.9-2.0)(SxFM)materials have been successfully synthesized using the sol–gel combustion method as thecathodes for IT-SOFC, and then characterized with X-ray diffraction (XRD), scanningelectron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), conductivity,electrochemical impedance spectroscopy (EIS) as well as the electrochemical performance.The thin ScSZ electrolyte with large-size was synthesized using the tape-castingmethod, which explored the cast formulations and sintering methods. And the conductivityof0.095S cm-1at800oC is measured with resistance method. The maximum powerdensities of a single cell reaches368mW cm-2. New casting method was improved forpreparing porous|dense|porous electrolyte substrate which can promote the surfaceroughness of the electrolyte in order to obtain suitable for making large electrolyte batteryexcellently, but it is difficult to control the thickness and further improvements are needed.Porous|dense ScSZ was synthesized using tape-casting method for impregnating SFManode material.70%pore-forming agent content of the substrate was chosen for preparation of nano-dipping SFM and SFM-SDC anode component. The maximum power densities of asingle cell fabricated with the SFM anode reaches708mW cm-2, while SFM-SDC anode819mW cm-2.A-site deficient SrxFe1.5Mo0.5O6-δ(x=1.9-2.0) materials have been successfullysynthesized using the sol–gel combustion method. All oxides have a perovskite structure.XPS, conductivity and EIS results indicated that the Sr-deficiency directly influences theconductivity and resistance of SxFM materials. S1.950FM possesses the highest electricalconductivity of33S cm-1. The deficiency in A-site can affect the concentration of cations inB-site, which contributes to changing the ionic conductivity of the ABO3materials, and theincrease of oxygen vacancies induced by the Sr-deficiency is also one of the factors thataffect the electrochemical properties. The maximum power densities of a single cellfabricated with the S1.950FM cathode reaches1083mW cm-2at800oC and S1.950FMcathode possesses favorable stability performance in the testing time.