Fabrication and Characterization of a Composite Ni-SDC Fuel Cell Cathode Reinforced by Ni Foam

Abstract

High-temperature fuel cells (namely, molten carbonate and solid oxide; MCFCs and SOFCs) require the cathode to be designed to maximize oxygen catalytic reduction, oxygen ion transport, electrical conductivity, and gas transport. This then leads to the optimization of the volume fraction and morphology of phases, as they are a pathway for electrons, ions, and gases to be continuous and self-interpenetrating. Apart from the functional properties, the cathode must be mechanically stable to prevent cracking during fuel cell assembly and operation. The manufacturing process of the composite cathode was optimized to meet such requirements in this research work. The tape casting technique and further firing process were used to fabricate the cathodes. The slurry for the green tape was composed of nickel (Ni), cerium oxide doped with samarium oxide (SDC), water (solvent), and an organic binder (which becomes pore space after firing). Each of these elements is necessary for the effective transport of specific species: electrons, oxygen, ions, and gas particles, respectively. Moreover, the nickel foam was embedded into the powder-based structure to improve mechanical strength. The study involved many technological issues, such as the effect of the SDC fraction on the cathode microstructure, mechanical strength, and chemical stability at high temperatures, and also involved environmental issues.

Structural, particle size distribution, and electrochemical behavior of double perovskite oxide doped Ce0.8Sm0.2O1.9 for intermediate temperature solid oxide fuel cells

“…Similarly, D50 and D75 are 1.4 µm and 1.70 µm; this indicates that 50% of the particles are below 1.4 m in diameter and 75% of the particles are below 1.70 µm in diameter, respectively. It is seen that the ultrasound test kit (LS-PO ( 6)) is able to help break up large agglomerates and narrow the particle size distribution [15]. The particle size of the SBSC70+SDC30 cathode is consistent with the cathode particle size, as shown in Figure 3 above.…”

The Microstructural Reconstruction of Variously Sintered Ni-SDC Cermets Using Focused Ion Beam Scanning Electron Microscopy Nanotomography

“…Modern solid oxide fuel cells (SOFCs), perspective devices for clean and efficient energy conversion, operate at temperatures between 600 and 800 • C. Yttrium-stabilized zirconia (YSZ) as a ceramic part of a cermet is normally replaced with ionically superiorly conductive samarium (SDC) or gadolinium-doped ceria (GDC) [1,2]. Specifically, at comparable temperatures, GDC or SDC exhibit ionic conductivities of nearly one order of magnitude greater than YSZ [3][4][5][6][7]. Since the anode side in a SOFC is the area where the oxidation of fuel gas occurs, an anode material must fulfil several important requirements: (i) it has to be highly catalytically active for the oxidation of the fuel gas, which is determined with the number of reaction sites; (ii) the anode has to exhibit chemical, morphological, and dimensional stability at the required operating temperatures in the reductive fuel gas environment; (iii) the anode material has to exhibit the Materials 2024, 17, 3068 2 of 19 greatest possible electronic-and ionic-conductivity to minimise ohmic losses and to promote the reaction of the fuel with oxide ions; (iv) it also has to exhibit chemical, mechanical, and thermal compatibility with adjacent cell components; and (v) the porosity of the anode must be modified to optimise the mass transport of fuel or gaseous product components.…”