Micro-Tubular Solid Oxide Fuel Cell Polarization and Impedance Variation With Thin Porous Samarium-Doped Ceria and Gadolinium-Doped Ceria Buffer Layer Thickness

Abstract

<jats:title>Abstract</jats:title> <jats:p>Porous buffer layers for anode-supported solid oxide fuel cells (SOFCs) have been investigated for many years with different thicknesses of the buffer layer in each study. In this work, micro-tubular SOFCs having samarium-doped ceria (SDC) and gadolinium-doped ceria (GDC) buffer layers are compared using the current-voltage technique, electrochemical impedance spectroscopy, scanning electron microscopy and energy dispersive x-ray spectroscopy. The thickness of the porous SDC and GDC buffer layer is investigated systematically with the thickness varying between 0.3–2.0 µm. The power density varies between 212 and 1,004 mW.cm−2 for samples having different SDC buffer layer thickness. Comparable changes occur for the SOFCs with a GDC buffer layer, but less variation in polarization losses resulted. Variation in electrochemical performance varies due to changes in ohmic resistance, cathode activation polarization, and interfacial reactions between the cathode and electrolyte materials.</jats:p>

Solid Oxide Fuel Cells with a Thin Film Electrolyte: A Review on Manufacturing Technologies and Electrochemical Characteristicses

“…Currently, the most studied microtubular cells are the anode-supported ones, as this configuration allows for the reduction of the ohmic losses [39,[110][111][112][117][118][119]. The supporting microtubes are usually made by phase inversion method, which has the flexibility in control and tailoring of the microstructure.…”

“…Anode-supported microtubular SOFCs with a diffusion barrier layer to mitigate the interaction of YSZ electrolyte and La0.6Sr0.4Co0.2Fe0.8O3- (LSCF) cathode, which exhibited excellent performance, were prepared by Milcarek et al [117] using the extrusion, dip-coating and wet powder spray techniques. YSZ electrolyte with a thickness of 22 m was dip coated onto the extruded NiO-YSZ tubes and sintered at 1400 °C for 4 h. Then a buffer layer of Sm0.2Ce0.8O2- (SDC) or Gd0.1Ce0.9O1.95 (GDC) was deposited by spraying and sintered at 1350 °C for 4 h. To complete the cell, the cathode layer of LSCF-SDC (weight ratio of 7:3) and LSCF-GDC (weight ratio of 7:3) was dip coated and sintered at 1100 °C for 2 h. The best electrochemical performance was demonstrated by the cell with the 1.7 m thick SDC buffer layer deposited by 105-step spraying: the OCV value reached more than 1.1 V, and the peak power density was about 1 W cm -2 upon supply of hydrogen as a fuel and air as an oxidant at 750 °C.…”

“…The microtubular SOFCs have a great potential for portable applications due to fast start-up, small size, and high electrochemical characteristics reported in multiple studies (see e.g. [112][113][114][115][116][117][118][119]). However, the degradation of the cells during the long-term operation remains a weak point.…”

Techno-Economic Assessment of CHP Systems in Wastewater Treatment Plants

“…An electrolyte membrane adjacent to the anode allows for the flow of the positive ions from the anode to another electrode (cathode) in the case of a polymer electrolyte membrane (PEM) fuel cell [69,70]. In the case of solid oxide fuel cells (SOFCs), O 2 ions are transported through the electrolyte from the cathode to the anode side [71]. The electrons move from the anode to the cathode via an external circuit.…”