Study Of Cathodic Current Collector And Ba Fe_0.95Bi_0.05O_3-δ Base Cathode For Solid Oxide Fuel Cells

Cathode current collector layer(CCCL) and cathode materials are important factors affecting the performance of solid oxide fuel cells(SOFC). To enhance the SOFC discharge performance, this paper studies the CCCL and Ba Fe0.95Bi0.05O3-δbased cathode material.CCCL slurry is Ag paste with 8 mass% of ethyl cellulose(EC), and the cathode is surround by Ag wire, after heat-treated, the CCCL keeps porous structure, the cathode discharge performance improved significantly. When added 8 mass% EC and 15 mass% SSZ into Ag slurry, The CCCL keeps microscopic pore structure at850℃. Adding 12 mass% EC into the LSM paste and Calcined at 1050℃ for 2 h,pore structure of LSM CCCL is appropriate, but when Ag as CCCL, the cathode performance is better. The interconnect is coated of LSM, When Ag network contact with it directly, the contact resistance is 2 mΩ·cm2, this scheme is suitable for collector.Ba Fe0.95Bi0.05O3-δ(BFB5) powder has perovskite structure, as a cathode material whose optimized sintering temperature is 1100℃.The cathodic polarization resistance of BFB5 is 0.22 Ω·cm2at 750 ℃. With increasing GDC content, the thermal expansion coefficient and electronic conductivity of BFB5-x GDC composite cathode material reduces, where in the range 600-800℃, BFB5 thermal expansion coefficient is 30.6×10-6 K-1, The maximum electronic conductivity of BFB5 reaches 4.4 S·cm-1 at 450℃. Ni O/YSZ|YSZ|GDC|BFB5 single battery’s total resistance is 0.33Ω·cm2 and the maximum power density is 1.61 W·cm-2 at 800℃.With the doping amount of Cu increasing, Ba Fe0.95-x Bi0.05 Cux O3-δ(BFBCx)cubic phase increases at room temperature, the thermal expansion coefficient BFBCx increases with Cu doping content increasing, while the maximum electronic conductivity temperature occurs delay. In BFBCx series cathode, maintaining good microstructure, BFBC5 cathode sintering temperature is 940 ℃, its cathode polarization resistance is 0.166 Ω·cm2 at 750℃. The single battery’s total resistance of Ni O/YSZ|YSZ|GDC|BFBC5 is 0.29 Ω·cm2 and the maximum power density is1.59 W·cm-2 at 800℃.