Highly Porous Anode for Application in High-Temperature Electrochemical Devices

A highly porous anode material (>70 vol %), co-precipitated nickel oxide and gadolinia doped ceria (NiO-CGO), which can be reduced to Ni-CGO to be used in electrochemical devices, has been fabricated using the direct foaming technique. The direct foaming technique produces small bubbles in colloidal suspensions to aid in the fabrication of porous ceramic structures. The NiO-CGO material has been prepared using a chemical co-precipitation process. Bubbles were introduced into the NiO-CGO using this method and the product was dried at room temperature followed by sintering in air and reduction in humidified hydrogen. The fabricated anode exhibited a porosity of about 80 %, and the porous anode could be sliced, lapped, and reduced without crumbling. The microstructure was investigated using high resolution (HR)-SEM revealing that the open pores with a size distribution ranging from nanometers to tens of microns. Electrochemical impedance spectroscopy (EIS) measurements were performed to investigate the feasibility of the pellets as anodes and determine the porosity influence on the electrical conductivity.