Effect of conductivity and adhesive properties of cathode current-collecting layer on cell performance inside stack for planar solid oxide fuel cells

摘要

Effects of conductivity and adhesive properties of cathode current-collecting layer (CCCL) on cathode contact resistance and cell performance inside a solid oxide fuel cell (SOFC) stack during operation are investigated by adding Al_2O_3 to the CCCL of (La_(0.75)Sr_(0.25))_(0.95)MnO_(3+δ) (LSM). The conductivity of LSM-15 wt% Al_2O_3 composite CCCL decreases from 141.6 S cm~(-1) to 23.7 S cm~(-1) at 800 °C, whereas its adhesion to SUS 430 interconnect and LSM-YSZ active cathode increases by 2.5 and 1.8 times, respectively. The area specific resistance (ASR) of SUS 430/ CCCL/LSM-YSZ sandwich at 800 °C is tested. The result shows that ASR of SUS 430/ LSM-15 wt% Al_2O_3 /LSM-YSZ sandwich is approximately 2.5 times smaller than that of the SUS 430/LSM /LSM-YSZ sandwich. The maximum output power density (MOPD) of the unit cell with LSM-15 wt% Al_2O_3 CCCL is slightly higher than that of the cell with pure LSM CCCL at 800 °C. The degradation rate of the unit cell with LSM-15 wt% Al_2O_3 CCCL is nearly 1/7 of the unit cell with pure LSM being discharged at a constant DC of 0.32 A cm~(-2) for about 100 h. Consequently, the addition of adhesive to CCCL is much more conducive to improve the long-term stability of the stack operation.