| Solid Oxide Fuel Cell(SOFC)is essentially a kind of power generator that convert the chemical energy in H2,CH4,natural gas and other hydrocarbon fuels directly into electricity.As a new generation of energy technology in the 21st century,SOFC has many advantages,including high energy density,stable mechanical properties,and wide fuel applicability,as well as environmental protection and pollution-free.Using metal or alloy as the SOFC anode support can not only improve the mechanical stability of SOFC and realize the rapid start-up of the stacks,but also reduce the material and faberication costs of SOFCs,which is expected to promote the commercialization of SOFC.The traditional metal support solid oxide fuel cell(Metal support solid oxide fuel cell,MS-SOFC)uses commercial alloys as the support,but commercial alloys have low catalytic reforming activity for CH4,which severely restricts the use of hydrocarbon fuel in MS-SOFC.In order to improve the catalytic reforming activity of SOFC metal support for CH4,this paper uses Ni-Co-Fe(NCF)alloy as the support of SOFC.CH4 is first reformed into H2 and CO in the Ni-Co-Fe alloy support,and then electrochemical reaction occurs in the Ni-YSZ functional layer.According to the independent reforming experiment of the NCF support,the influence of the Co doping amount on the catalytic activity of the support was analyzed,and the influence of different component metal supports on the electrochemical stability of MS-SOFC in CH4 was studied.MS-SOFC,with Ni-YSZ cermet as functional anode,La0.8Sr0.2Mn O3 coated Ba0.5Sr0.5Co0.2Fe0.8O3 as cathode and YSZ(Y2O3 stabilized Zr O2)as electrolyte,are successfully fabricated by tape molding-screen printing-sintering process with Ni O?Co O and Fe O.The SOFC support is mainly composed of Ni O,Ni Fe2O4 and Co Fe2O4 spinel phases after high-temperature sintering,and the support is transformed into Ni-Co-Fe alloy after reducing in H2 at 650°C for 2h.The independent reforming experiment of the metal supports showed that with the increase of Co doping,the catalytic reforming activity of the support for CH4 increased,and NCF631 showed a higher CH4 conversion rate and stability.The maximum peak power density of NCF811,NCF721 and NCF631 cells in H2-3mol.%H2O is basically the same.However,when tested in CH4-3mol.%H2O,compared with NCF811 and NCF721,NCF631shows a higher peak power density in 650-750?,the higher peak power density is mainly due to the higher CH4 reforming activity of the NCF631 support.The stability test of cells at 750?,400 m A·cm-2 constant current shows that NCF721 and NCF631 run stably for 24 hours in CH4-3mol.%H2O,and the voltage has almost no attenuation. |
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