Morphological control of electroless plated Ni anodes: Influence on fuel cell performance

The suitability of nickel electroless plating for anode deposition on electrolyte-supported solid oxide fuel cells (SOFCs) based on yttrium-stabilised zirconia (YSZ) has been studied. A deposition technique was developed and characterisation is presented with respect to microstructure, strength and performance of the resultant anode. The study was carried out on YSZ disk-shaped pellets sintered at different temperatures ranging from 1000 °C to 1400 °C with analysis of the influence of sintering temperature on the Ni–YSZ interface microstructure and fuel cell performance. Lower pre-sintering temperature resulted in higher Ni penetration into the YSZ matrix, forming a graded anode and improving the anode–electrolyte interfacial strength. The optimised electrode showed good mechanical stability under redox cycling which resulted in an enhancement of electrode porosity. Complete fuel cells were tested at 800°C with 5% H2 and air after a porous La0.2Sr0.8Co0.8Fe0.2O3 − δ (LSCF) cathode layer had been deposited by slurry coating. The higher Ni penetration on YSZ substrates pre-sintered at low temperature resulted in an improvement of one order of magnitude of power output compared to a cell in which a metal Ni anode was coated over a fully dense (i.e. high pre-sintering temperature) electrolyte surface.