Highly efficient and stable fuel-catalyzed dendritic microchannels for dilute ethanol fueled solid oxide fuel cells

Abstract

Highly efficient utilization of low calorific value fuels is a major challenge for the current economic society. As an electrochemical device, solid oxide fuel cells (SOFCs) offer an efficient approach, but the performance is limited by the concentration loss. Hence, a dendritic fuel microchannels for dilute ethanol-fueled SOFCs is designed by phase inversion technique to accelerate the mass transport and improve the conversion efficiency in this study. Based on the three-dimensional X-ray computed tomography technology, the porosity of the obtained dendritic microchannels is around 40%, and the absolutely permeability is 0.31 μm2, which can guarantee the efficient fuel transport. Benefiting from the dendritic microchannels, the electrochemical performance increases from 363.1 mW cm−2 to 713.8 mW cm−2 at 750 °C using 10% ethanol as fuel, and the concentration loss can be negligible. In addition, the fuel utilization of dendritic microchannels increase from 34.6% to 97% by reducing the ethanol concentration from 30% to 10% at 0.3 V. The corresponding maximum power density only decrease 7% at 750 °C (677.1 mW cm−2 vs 632.7 mW cm−2). All the results demonstrate that the design of dendritic microchannels for SOFCs is an efficient solution to accelerate the gas diffusion and improve the conversion efficiency of the low calorific value fuels.