(316e) Recent Progress on Ni-Based Cermet Anodes for Intermediate-Temperature Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are promising energy devices converting chemical energy of fuels directly into electricity with a high efficiency. With traditional Ni-based cermet anode and Ce_0.8Sm_0.2O_1.9 (SDC)-carbonate composite electrolyte, we obtained a maximum power density (P_max) of about 1.7 W cm^-2 at 650 ^oC with H₂ as the fuel. However, Ni suffers from serious carbon deposition with hydrocarbons as fuels.

As a cooperation with Professor Schwank, a CH₄-fuelled single cell with Ni-SDC anode and 120 μm-thick SDC electrolyte layer showed a P_max of 670 mW cm^-2 at 700 ^oC. The performance dropped 3.7% after the cell discharged at 600 ^oC for 72 h. An addition of a small amount of Sn in the anode showed a positive effect on the stability of the anode, and the performance drop of the cell decreased to 1.51%.

In a recent work, we synthesized Ni-SDC anode powder with a three-dimensionally ordered macroporous (3DOM) structure using close-packed poly(methyl methacrylate) (PMMA) spheres as the template. The investigation on the structure and surface property of Ni/3DOM-SDC composite anode reveals the synergetic effect between Ni and SDC phases, facilitating the electro-oxidation of methanol and improving the resistance to coking. A single cell with that anode and a 500 μm-thick SDC-carbonate composite electrolyte exhibits a maximum power density (P_max) of 1.63 W cm^-2 at 700 ^oC with gasified methanol as the fuel. In another work, Sn was doped in SDC, which improved the activity of lattice oxygen, resulting in remarkably enhanced catalytic activity of the Ni-based anode on the electrochemical oxidation of CH₃OH. The cell with Ni-SnSDC anode exhibits P_max of 1.99 and 2.11 W cm^-2 at 700 ℃ with H₂ and methanol as fuels, respectively. The coking resistance of the anode is also improved significantly.