Direct Utilization of Pure and Denatured Ethanol in Metal Supported Solid Oxide Fuel Cells

Abstract

Metal supported solid oxide fuel cells (MS-SOFC) are integrated with high entropy alloy reforming catalyst for direct internal reforming utilization of pure ethanol, methanol, and denatured ethanol to generate electricity. Internal reforming SOFCs have advantages over the external reforming SOFCs in terms of cost, energy efficiency, and space-saving. Performance and durability with denatured ethanol, mimicking the compositions of widely commercially-available bio-ethanol, varies dramatically with the composition of the denaturant. This evaluation of bio-ethanol fuel for SOFC application extends beyond the previous literature focusing on high-purity ethanol. Mitigation of carbon deposition is critical to extend the lifetime of MS-SOFCs operating with ethanol. Conventional Ni catalyst shows rapid carbon deposition, and in contrast the HEA catalyst has excellent resistance to carbon deposition. The HEA also enables complete internal reforming without localized cooling, resulting in high power density >0.8 W/cm2 at 700°C. Long-term operation (500-1000 hours) at the operating temperature of 600-800°C will be presented. Various strategies are applied to improve the cell stability. The effect of impurities and fuel compositions on the cell performance and stability is evaluated. Other degradation factors such as Cr evaporation and catalyst agglomeration are analyzed by SEM-EDS and EIS. It is found that MS-SOFCs are promising for direct utilization of bio-ethanol, offering a path to rapid-start, carbon-neutral operation.