Morphological studies of macrostructure of Ni–CGO anode hollow fibres for intermediate temperature solid oxide fuel cells

In this study, Ni–CGO anodes hollow fibre with controlled asymmetric structures, i.e. adjustable ratios between thickness of the outer sponge-like and the inner finger-like layers, have been developed for intermediate temperature micro-tubular solid oxide fuel cells (SOFCs), using a combined phase inversion/sintering technique followed by a post-reduction process. The control over the asymmetric structure is achieved by employing ethanol as a non-solvent to adjust the initial properties of the spinning suspensions, which affects the phase inversion process and results in a series of asymmetric structures from very thin sponge-like layer supported on considerably thicker finger-like layer (0 wt.% ethanol), to the one consisting of nearly a full sponge-like structure (35 wt.% ethanol). The characteristic of the anode hollow fibre is found significantly affected by such changes in asymmetric structures. For example, the experimental results show that the mechanical strength and electrical conductivity increase up to 241 MPa and 11,246 S cm−1, respectively, but with high resistance for the fuel transport for a full sponge-like structure of the fibres prepared with 35 wt.% of ethanol.