Impregnation of nickel foils with nanocrystalline ceria as anodes for solid oxide fuel cells SOFC

Solid electrolytes with good oxygen-ion conductivity are of particular interest for application in high-temperature fuel cells. This paper focuses on the manufacturing of the anode, acting as substrate for the multilayer system anode / electrolyte / cathode in a SOFC. Anodes build as porous composites, mixed of nickel and gadolinium doped ceria GDC10 are bound to percolation theory and tend to over-potential loss when the metal parts corrode. In pure-nickel anodes the conductive metal particles are heavily networked. Partly coating these metal anodes with nanometer-ranged ceramic films provides a necessary ionic conductivity of the anode. In this way over-potential loss is reduced and the electrochemically active area is expanded. This advanced anodic structure is conventionally achieved by electrochemical vapor deposition. An alternative manufacturing route is presented here. The anodes were prepared by pressing of nickel powder with 20 - 45 microns in diameter and then electrophoretically impregnated subsequently with nanometer-sized GDC powders. The nanoparticles infiltrate the open pore channels of the nickel specimen and form a layer on the surface of the nickel particles. Green bodies and sintered anodes were analyzed by SEM.