Research in the field of solid oxide fuel cells in recent years has primarily focused on the improvement of the electrochemical performance of the cell, especially reduction of cathodic overpotential. The mechanical performance of SOFCs has been largely neglected. Thermomechanical performance issues related to the operation of cells have only been studied in the recent past.
To reduce ohmic losses, researchers fabricate thinner components with upwards of 50% porosity, thereby diminishing the strength of the entire cell. Additionally, anodic polarization losses tend to be lower than cathodic, a trait that many researchers would like to exploit by making anode supported cells. Oxidation and reduction of the anode material leads to degradation in SOFC performance during cyclic operation. Anode supported cells must continue to flow fuel gas during cool-down to prevent re-oxidation of nickel, which is the common catalyst in these electrodes.
The bulk of the research presented here focuses on increasing the strength and mechanical integrity of the solid oxide fuel cell by providing an internal structural framework of zirconia within the electrode. The honeycomb structure used provides mechanical support, allowing for a thinner electrode. In addition to increasing the mechanical strength, the zirconia substructure mitigates expansion mismatch issues between the electrolyte and electrodes in both anode- and cathode-supported cells. The concept may also provide a solution to catastrophic mechanical failure of anode materials during cell cycling of anode-supported SOFCs --Abstract, page v