Study On Electrical Performance Of Solid Oxide Fuel Cell With Hollow And Symmetric Structure

Solid oxide fuel cell(SOFC)technology is a clean and efficient comprehensive energy utilization technology.The all-solid-state structure allows it to be made into various shapes.The hollow symmetrical double-cathode structure SOFC is a new type of structure SOFC developed in recent years.The new structure SOFC has many advantages such as high structural strength and strong resistance to oxidation and reduction.The rapid thermal cycling stability and long-term stability of the new structure SOFC are thoroughly studied,and the performance degradation laws and influencing factors of the new structure SOFC during the rapid thermal cycle and long-term operation are analyzed.It has important practical significance for accelerating the industrialization process of SOFC.The main contents of this dissertation include:(1)Both hollow symmetrical double-cathode structure solid oxide fuel cells and stacks have good fast thermal cycling stability.The performance degradation of the cell during the 100 rapid thermal cycles mainly occurs in the first 34 times,and the decay rate is about 0.89%per cycle.And the performance degradation caused by the loose interface between the cathode and the cathode current collecting plate.which can be recovered by secondary pressure operation.(2)The hollow symmetric double-cathode structure solid oxide fuel cell has good long-term stability.Under appropriate operating conditions,the new structure cell exhibits excellent electrochemical performance and long-term stability.The cell runs at a constant current of 0.4A/cm~2 for 200h,and the degradation rate is only 2.28%/100h.The corrosion of the cathode current collector plate may be the main reason for the cell performance decay.After adopting brazed sealed technology,the new structure SOFC is operated at 0.30A/cm~2 current density constant current for 114h,0.20A/cm~2 current density constant current for 310h,and the degradation rate is 0.99%/100h,2.21%/100h,respectively.Compared with the glass ceramic sealed cell,the degradation rate of the brazed sealed cell has a great improvement,which indicates that the brazed sealed technology effectively improves the long-term stability of the new structure SOFC.(3)The output performance of the SOFC stack with hollow symmetrical double-cathode structure decayed quickly,with a decay rate of 12.56%/100h,which was mainly affected by the output performance of the single cell.The intermediate connectors had little effect on the output performance of the stack in a short time.The output performance of the new structure SOFC is not only related to the cell’s own power generation performance,but also to the thickness of the anode support,and the interconnection between two independent cathodes.The latter is the main reason for the large difference in cell output performance and poor stability,and the main reason for the large difference in output performance and poor stability of the new structure SOFC stack.Improving the connection between the two independent cathodes of the new structure SOFC can effectively improve the stability of the cell’s and the stack’s output performance.