Preparation And Properties Of Intermediate Temperature Solid Oxide Fuel Cell Materials Pr₂NiO_4+?and Ce_0.8Nd_0.2O_1.9

The commercialization of solid oxide fuel cells?SOFCs?has made the development of low-temperature electrolytes and novel cathode materials become the focus of current fuel cell research.At medium and low temperatures,CeO₂ based electrolytes have been widely studied as SOFC electrolyte materials due to their excellent electrical conductivity.However,the high sintering temperature of CeO₂-based electrolytes limits the commercialization of SOFCs.Compared with traditional cathode materials,A₂BO₄-type perovskite-like oxides have become research hotspots in recent years due to their high oxygen surface exchange coefficient and diffusion coefficient,as well as good thermal compatibility with electrolytes.Among them,Pr₂NiO₄ with K₂NiF₄ structure has become a promising active oxygen electrode material for medium-temperature solid oxide fuel cells?IT-SOFCs?due to its high oxygen catalytic activity.In this paper,a Sol-Gel method and a Solid State Mixing method are used to prepare Pr₂NiO₄?PNO?-Ce_0.8Pr_0.2O_1.9?PCO?composite cathode materials.Sol-Gel method is used to prepare Nd₂O₃ doped CeO₂(Ce_0.8Nd_0.2O_1.9,NDC)Electrolyte.The feasibility of PNO-PCO composite cathodes as SOFC cathode materials was studied.The effects of the addition of CoO/Bi₂O₃ sintering aids on the sintering behavior,microstructure and conductivity of NDC electrolytes were investigated.The results show:?1?The PNO-PCO composite cathodes prepared by both methods are pure phases and exhibit good chemical compatibility with Ce_0.8Gd_0.2O_1.9?GDC?electrolyte.The PNO-PCO of the composite cathode obtained by the sol-gel method has uniform grain growth,good porosity,a large area in contact with oxygen,a large number of active sites for oxygen reduction reactions,and a significant reduction in polarization resistance.Electrochemical measurement results show that the polarization resistance of PNO-PCO is 0.09??cm² at800°C.The electrolyte-supported single cell with the configuration of NiO-GDC/GDC/PNO-PCO has a maximum output power density of 0.57 W?cm^-22 at 800°C and shows good stability in a long-term stability test at 120 h.?2?Individually or synergistically add a small amount of Bi₂O₃ and CoO sintering aids to the NDC electrolyte.Addition of proper amount of Bi₂O₃ and CoO to NDC can the decrease the sintering temperature,the relative density can be increased,and effectively enhance the conductivity without changing the crystal structure.Moreover,the NDC electrolyte doped with Bi₂O₃-CoO dual sintering aid is more effective than that using Bi₂O₃or CoO single sintering aid,and has higher density and electrical properties under the same conditions.At 800°C,the total conductivity of NDC electrolyte doped with Bi₂O₃-CoO double sintering aid is 55%,34%and 19%higher than that of NDC,CoO and Bi₂O₃ single sintering aid doped NDC,respectively.