Study On La（NiFe）O₃-based Anode Material For Solid Oxide Fuel Cells

Two kinds of symmetrical structure supported by Sc2O3stabilized ZrO2(SSZ)and Ce0.8Gd0.2O1.9(GDC), LNF/SSZ/LNF and LNF+GDC/GDC/LNF+GDC, wereprepared based on the perovskite anode material LaNi0.6Fe0.4O3-δ(LNF). Structuralstability and electrochemical properties were investigated for LNF material inreducing atmosphere.The compatibility research showed that LNF and SSZ mixed powder couldgenerate insulated phase La2Zr2O7through the LNF anode material of symmetricstructure fuel cells supported by SSZ. The stability of LNF was investigated, whichindicated that LNF became unstable as reducing atmosphere H2existed anddecomposed into La2O3, FeNi3and unknown phase. The ohmic resistance andpolarization resistance increased as increasing the calcination temperature. Thesymmetrical structure fuel cells of LNF/SSZ/LNF calcined at1150oC showed themaximum power densities of45,82and145mW cm-2at750,800and850oC with H2as the fuel, respectively. The single cell performance decreased after reduction in H2atmosphere for10h with the maximum power densities of36,64,87and105mWcm-2at750,800,830and850oC. When the fuel cell was running on CH4, themaximum power densities of12,29,57and88mW cm-2were investigated.GDC peaks shifted to lower angle because of elements mutual diffusion betweenLNF and GDC as increasing the temperature through LNF anode material research ofsymmetric structure fuel cells supported by GDC. The electrode material displayedthe best electrochemical performance when the calcination temperature was set in1200oC and GDC+LNF mixing ratio was3:7. The optimum amount of pore-formingagent was5wt%for the single cell comparded to0and10wt%. The single cellshowed the maximum power densities of36,61,100and171mW cm-2at600,650,700and750oC with H2as the fuel, respectively. The maximum power densities of22,25,55,82and98mW cm-2were observed as running on the CH4fuel at600,650,700,750and800oC, respectively.The symmetrical helf-cell prepared by impregnation method in CH4atmosphererevealled that the impedance decreased at first and then became stable at750oC. Theimpedance reduced to0.46Ω cm2from the initial value of0.94Ω cm2.