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High Performance Solid Oxide Electrolysis Cells with Hierarchically Porous Ni-YSZ Electrode 

Thursday, 27 July 2017: 11:20
Atlantic Ballroom 1/2 (The Diplomat Beach Resort)
L. Lei (University of South Carolina), Y. Chen (School of Materials Science and Engineering, Georgia Tech), Y. Zhang (Harbin Institute of Technology), T. Liu, Y. Wang (Wuhan University), and F. Chen (University of South Carolina)
In solid oxide electrolysis cells (SOECs), the microstructure of the cathode (Ni-YSZ) has a great influence on the electrochemical performance of cells. In this study, novel hierarchical Ni-YSZ electrode substrates with open channel pores have been fabricated by freeze-drying tape casting (FTC). The microstructure characterization of the the Ni-YSZ electrode substrates, using SEM, mercury intrusion, 3D X-ray microscopy and gas permeability, shows that Ni-YSZ electrode substrates fabricated by FTC have large porosity and low tortuosity factor, which are beneficial for gas transport. The SOECs with the Ni-YSZ electrode substrates fabricated from FTC display excellent performance ( -0.95 A cm-2 with 1.3 V at 750 oC) in the electrolysis mode, which is twice of those with the conventional sponge-like Ni-YSZ electrode substrate fabricated from dry-pressing. Furthermore, compared with the cell performance in the fuel cell mode, the advantages of the hierarchically porous Ni-YSZ electrode substrates are more obvious in the electrolysis mode, which may be due to the slower diffusion of H2O and CO2, compared with H2.