| The solid oxide fuel cell (SOFC) is an electrochemical device, which is capable of converting chemical energy of fuel into electrical energy at the high temperature directly. SOFCs are environmentally friendly and have the advantage of energy conversion rate. In the context of energy crisis and environmental pollution, more and more people pay close attention to the fuel cells. However, combined with the research status at home and abroad, the main problems are difficult preparation process, anode carbon deposition and high operating costs. The paper mainly studies the following contents in order to solve the above problems. In the case of reducing operational temperature with methane as fuel, different anode structures are researched to improve the power performance and different anode material was researched to enhance the resistance to carbon deposition and the stability.New pore forming agent is researched to construct the different anode structure, which is formed by adding the absorbent cotton of ductile filamentous material into the anode. Porous NiO-YSZ anodes added 3%,5%,7% and 10% absorbent cotton were prepared, respectively. For comparison, the traditional NiO-YSZ anode with flour pore forming agent was prepared. Using YSZ as electrolyte, LSM+YSZ as cathode, five groups of single cells were test power performance. SEM results showed that the particles of metal ceramic were fully attached to the cotton silks, the diameter of which was about 10～20 μm. Absorbent cotton maintained good continuity after grinding and was evenly distributed in the anode material. By comparison, NiO-YSZ anode with 5% absorbent cotton was provided with the best electrical properties, which were much higher than that of the traditional single cell. The maximum power densities of NiO-YSZ anode with 5% absorbent cotton were not less than 900 mW·cm-2 and 273.92 mW·cm-2 with hydrogen and dry methane as fuel at 800℃. Experimental results demonstrate that the absorbent cotton used as pore forming agent is conducive to building more reasonable anode microstructure. High porosity and long pore channel structure formed increase the three-phase interface of the anode and improve power generation performance of SOFC.Hard template method was used to prepare tubular YSZ and liquid immersion method was used to prepare the anode material with Ni0.5Cu0.5Ox coating tubular YSZ. YSZ of hollow fiber tubes was used as the skeleton, inner and outer surfaces of that adequately were coated with NiO and CuO without nickel copper alloy phase. The diameter of tubular YSZ was about 4 μm and the metal particle size was about 90 nm so that the coating effect is good. Compared with the initial voltage, after 100 hours of long term stability test, the final voltage of single cells decreased by 5.27% and 0 with CH4 and 97% CH4+3% H2O as fuel. The results show that the addition of water vapor can enhance the anti-carbon capacity of the single cell. When Ni0.5Cu0.5Ox coating tubular YSZ material is used as anode material, SOFC has obvious inhibitory effect of carbon deposition with 97% CH4+3% H2O as fuel.In addition, adding an alkali metal oxide BaO and a rare earth oxide SDC into anode material to inhibit carbon deposition, three kinds of single cells were prepared and tested power generation performance and anti-carbon deposition capacity. The single cell with Ni0.5Cu0.5Ba0.05Ox coating tubular SDC as anode had the best electrochemical performance and anti-carbon deposition capacity. The maximum power densities with hydrogen and dry methane as fuel were 535.18 mW·cm-2 and 384.54 mW·cm-2 at 800℃, while the performance of the single cell did not decline after running 100 hours in dry methane atmosphere. The results show that tubular electrolyte structure prepared by hard template method is propitious to improve the anode microstructure and inhibit anode carbon deposition. Furthermore, adding Ba and SDC into anode material can improve the electrical performance and long-term stability. |
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