Electrochemical study on the effect of catalytic current collecting layer on thin film La0.6Sr0.4Co0.8Fe0.2O3-delta (LSCF) cathode
Sanghoon Lee1, Wonjong Yu, Wonyeop Jeong, Taehyun Park, Gu Young Cho#, Suk Won Cha#
In this study, catalytic current collecting layer (CCCL) was added to thin-film La0.6Sr0.4Co0.8Fe0.2O1-δ (LSCF) cathode for low-temperature solid oxide fuel cells to improve both in-plane resistance and catalytic activity. Pt, Pd, Cu, Ag, and Au were applied as CCCL of thin-film LSCF cathode. The thickness of the CCCL was varied from 100 nm to 300 nm. These CCCLs were deposited by sputtering on PLD-deposited LSCF cathode on a single-crystalline YSZ pellet. By adding the CCCLs, the maximum power density improved compared to the bare LSCF cathode cells. It was found that Pt, Pd, and Ag CCCLs improved both ohmic and faradaic impedance as the CCCLs’ thickness increased. However, for Cu CCCL, the thicker layer did not enhance the performance. The Pt CCCL cell showed the highest peak power density with the thickest layer. However, Au exhibited a noteworthy performance despite thinner thickness compared to all other materials. It turned out electronic conductivity of raw materials is dominant for the performance enhancement. The electrochemical performance was investigated through polarization curves and Nyquist plots. Also, long-term stabilities were measured with potentiostat mode. The microstructure of CCCLs was investigated through FIB-SEM and FE-SEM. Crystal structures of CCCL-added LSCF were studied through XRD.