A corrugated mesoscale structure on electrode–electrolyte interface for enhancing cell performance in anode-supported SOFC

Abstract

For enhancing the power density of a solid oxide fuel cell, mesoscale-structure control of electrode–electrolyte interfaces in an anode-supported cell is proposed. We define ‘mesoscale’ as a size range of the order of 10–100 μm which is larger than the ‘microscale’ of electrode particles but smaller than the ‘macroscale’ of cell geometries. Mesoscale-structure control enlarges the electrode–electrolyte interface, and this enlargement extends an active electrochemical reaction zone where a charge-transfer reaction occurs actively near the interface. A corrugated mesoscale electrolyte was adopted which enlarged the interface structures of both anode and cathode sides. We performed a 2-D numerical simulation, and discussed the effects of such structure not only on the overall performance but also on the detailed distributions of electric potentials, gas concentrations and local electrochemical reaction rate. As a result, it was observed that the corrugated mesoscale structure reduced both activation overpotential and ohmic loss by ion transport, and hence enhanced the power generation performance. When the interface area enlargement factor was 1.73, an enhancement of a power density having a maximum value of 59% was achieved with the mesoscale-corrugated cell rather than with the flat cell.