(404j) Ni-Based Cermet Anode with a Three-Dimensionally Ordered Macroporous Structure for Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are promising energy devices with high energy efficiency and low emissions [1]. Using hydrocarbons instead of hydrogen as fuels is one of the major advantages of SOFCs. The most common anode of SOFCs consists of metallic Ni and an ionic conducting ceramic phase. However, Ni suffers from not only aggregation at a high temperature, but also serious carbon deposition with hydrocarbons as fuels [2]. The optimization of anode structure is recognized as an efficient way to solve those problems.

In this work, Ni-samarium doped ceria (SDC) with a well-controlled structure is studied as an anode material of SOFCs. SDC framework with a three-dimensionally ordered macroporous (3DOM) structure was synthesized using close-packed poly(methyl methacrylate) (PMMA) spheres as the template. 10 wt% Ni catalyst was added in the SDC scaffold through impregnation. The agglomeration of Ni nanoparticles in the anode is effectively prevented by the “confinement effect” of the SDC framework. X-Ray diffraction results and transmission electron micrographs confirm the formation of Ce_1-xNi_xO₂ solid solution, which induces abundant oxygen vacancies. The investigation on the structure and surface properties of Ni/3DOM-SDC composite anode reveals the synergetic effect between Ni and SDC phases, facilitating the electro-oxidation of H₂ and methanol fuels, and improving the resistance to coking. A single cell with Ni/3DOM-SDC anode and SDC-carbonate composite electrolyte exhibits a maximum power density of 1633 mW cm^-2 at 700 ^oC with gasified methanol as the fuel, much higher than that of the cell with conventional Ni-based anodes without the 3DOM structure under the same condition.

References

[1] Z. Zhan, S.A. Barnett, Science, 308 (2005) 844.

[2] A.A.A. da Silva, N. Bion, F. Epron et al., Appl. Catal., B, 206 (2017) 626.