A novel anode for solid oxide fuel cells prepared from phase conversion of La0.3Sr0.7Fe0.7Cr0.3O3-delta perovskite under humid hydrogen

作者：Chen, Min^*; Hu, Yang; Chen, Dongchu; Hu, Huawen; Xu, Qing^*

来源：Electrochimica Acta, 2018, 284: 303-313.

DOI：10.1016/j.electacta.2018.07.132

• Solid oxide fuel cell
• Oxide anode
• Phase conversion
• Electrodics
• Fuel flexibility

A novel anode for solid oxide fuel cells (SOFCs), consisting of a Ruddlesden-Popper compound, La0.6Sr1.4Fe0.4Cr0.6O3.8, with in situ exsolved alpha-Fe nanoparticles (RP-LSF + Fe), is prepared from the phase conversion of the La0.3Sr0.7Fe0.7Cr0.3O3-delta (LSFCr-3) perovskite under humid H-2 at 800 degrees C. On the surface of the RP-LSF thorn Fe anode, Fe cations are presented to be a mixture of Fe2+ and Fe3+, of which the average valence is lower than that in the bulk (Fe3+). The coverage of atomic hydrogen on the RP-LSF thorn Fe anode is over 0.8 in the pH(2) range of 0.017-0.27 atm, implying a significant effect of these small amount (similar to 8 mol % on the surface) of exsolved Fe nanoparticles (similar to 200-300 nm) on promoting the dissociative absorption of H-2. The charge transfer resistance is found to be closely related to the concentration of surface oxygen vacancies of the oxide matrix. The addition of catalytic amount of Ni (1-3 wt.%) greatly improves the fuel flexibility of the RP-LSF thorn Fe anode. Furthermore, it contributes to acceleration the phase conversion of the LSFCr-3 perovskite and reduced time for in situ preparation of the RP-LSF thorn Fe anode. The RP-LSF thorn Fe anode with 2.7 wt.% Ni exhibits a stable cell performance under 2.7% H2O+1:1-(H-2:CO) and 2.7% H2O + CH4 for similar to 30 h. It costs shortest time (30 h) to reach a stable cell voltage of 0.76 V at a galvanostatic current density of 0.25 A/cm(2) under humid H-2, which is clearly an active and stable anode material for SOFCs.

• 出版日期2018-9-10
• 单位佛山科学技术学院; 武汉理工大学