Anchoring of Infiltrated Nickel Electro-Catalyst by Addition of Aluminum Titanate

Abstract

Solid oxide fuel cell electrodes based on catalyst coatings offer substantial potential for creating improved anode and cathode structures. Infiltrated anodes based on nickel metal can yield finer catalyst phase distribution at volumetric concentrations well below percolation for traditional cermets. The coarsening of nickel after high temperature thermal treatment poses substantial degradation to the deposited structure, therefore, methods of anchoring the nickel metal to the yttria-stabilized zirconia (YSZ) scaffold have been evaluated to stabilize fine scale electro-catalyst particles. Metastable aluminum titanate was introduced into the porous YSZ anode scaffold to facilitate a step-wise chemical reaction in the formation of nickel aluminate followed by zirconium titanate to anchor the nickel metal catalyst. SEM observation of thermally treated nickel infiltrated scaffolds indicates excellent preservation of the nickel network at 800°C for 72 h. Electrochemical tests show not only decreased degradation rates, but also increased initial performance levels due to the additive.