Nanostructured BaCo0.4Fe0.4Zr0.1Y0.1O3-δ Cathodes with Different Microstructural Architectures

Lowering the operating temperature of solid oxide fuel cells (SOFCs) is crucial to make this technology commercially viable. In this context, the electrode efficiency at low temperatures could be greatly enhanced by microstructural design at the nanoscale. This work describes alternative microstructural approaches to improve the electrochemical efficiency of the BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY) cathode. Different electrodes architectures are prepared in a single step by a cost-effective and scalable spray-pyrolysis deposition method. The microstructure and electrochemical efficiency are compared with those fabricated from ceramic powders and screen-printing technique. A complete structural, morphological and electrochemical characterization of the electrodes is carried out. Reduced values of area specific resistance are achieved for the nanostructured cathodes, i.e., 0.067 Ω·cm2 at 600 °C, compared to 0.520 Ω·cm2 for the same cathode obtained by screen-printing. An anode supported cell with nanostructured BCFZY cathode generates a peak power density of 1 W·cm−2 at 600 °C.

Performance of NiO/YSZ anode-supported solid oxide fuel cell fueled with landfill gas stream

Generating electrical energy from landfill gas (LFG) is a challenge due to its low conversion efficiency. In this study, performance of a NiO/yttria-stabilized zirconia (NiO-YSZ) anode-supported cell operating with LFG feed stream was evaluated. This study investigated the potential of solid oxide fuel cells (SOFC) to produce electricity from LFG generated in pilot scale anaerobic municipal solid waste bioreactors. During the initial experiments, power generation was achieved in the SOFC with direct feeding of the LFG. Different feed flow rates (10 25 mL/min) and varying temperature conditions (700 800 °C) were also investigated to define the optimal conditions. Experiments were carried out at different feed rates and the successful results obtained from 10 mL/min and 20 mL/min feed speeds. It was also observed that the maximal power values were between 0.10 0.11 Watt/cm2 for all experiments. This study showed that SOFCs can provide significantly higher energy efficiencies than steam engines for LFG conversion into electrical energy.

Performance of Pressurized Anode Supported Solid Oxide Fuel Cell

A commercially available Anode Supported Cell (ASC) with an active area of 81 cm2 was characterized at pressures up to 9 bar at 750 °C using a custom-built pressurized test stand. Open Circuit Voltage (OCV) measurements of the cell indicated the existence of an intercell leak due to a cracked cell. Voltage characteristic curves were measured at 1, 3, and 9 bar using 50/50 N2/H2 (1.2 SLPM) and bottled air (1.5 SLPM). Measured current density at 0.70 V increased from 0.37 A·cm−2 to 0.43 A·cm−2 as a result of pressurization from atmospheric to 9 bar. Subsequent measurements were taken while flowing 100% dry hydrogen at 1.5 SLPM and 100% oxygen at 1.5 SLPM. Under these conditions at 9 bar the current density increased to 0.5 A·cm−2. The OCV and peak power density increased more than suggested by theory, suggesting that the balanced anode and cathode flow rates reduced the pressure differential across the cell resulting in less leakage. These preliminary measurements validate the significant potential for improved operational performance under pressurized conditions.