High‐Performance Silver Cathode Surface Treated with Scandia‐Stabilized Zirconia Nanoparticles for Intermediate Temperature Solid Oxide Fuel Cells

Abstract

This work introduces a novel silver composite cathode with a surface coating of scandia‐stabilized zirconia (ScSZ) nanoparticles for application in intermediate temperature solid oxide fuel cells (IT‐SOFCs). The ScSZ coating is expected to maximize the triple boundary area of the Ag electrode, ScSZ electrolyte, and oxygen gas, where the oxygen reduction reaction occurs. The coating also protects the porous Ag against thermal agglomeration during fuel cell operation. The ScSZ nanoparticles are prepared by sputtering scandium‐zirconium alloy followed by thermal oxidation on Ag mesh. The performance of the solid oxide fuel cells with a gadolinia‐doped ceria electrolyte support is evaluated. At temperatures <500 °C, our optimized Ag‐ScSZ cathode outperforms the bare Ag cathode and even the platinum cathode, which has been believed to be the best material for this purpose. The highest cell peak power with the Ag‐ScSZ cathode is close to 60 mW cm−2 at 450 °C, while bare Ag and optimized Pt cathodes produce 38.3 and 49.4 mW cm−2, respectively. Long‐term current measurement also confirms that the Ag‐ScSZ cathode is thermally stable, with less degradation than bare Ag or Pt.

Opportunities, Challenges and Prospects for Electrodeposition of Thin-Film Functional Layers in Solid Oxide Fuel Cell Technology

“…To prevent particle agglomeration in a porous Ag layer, researchers considered the use of composite cathodes, in which Ag particles were coated with a layer of an oxygen-conducting electrolyte material. For this purpose, various technologies were applied such as aerosol-assisted chemical vapor deposition (AACVD) [ 67 ], atomic layer deposition (ALD) [ 68 ], sputtering [ 69 ], and infiltration [ 70 ].…”

Review on process-microstructure-performance relationship in ALD-engineered SOFCs

“…(1) ALD oxide on metallic cathode ALD oxide overlayers (or overcoatings, capping layers), e.g., MnO x [31], ZrO 2 [28], SnO 2 [29], doped ZrO 2 [30,32], CeO x [33], on metal cathodes have been actively researched in recent years [28][29][30][31][32] because they can compensate for the low thermal stability of porous metal electrodes, and in some cases, can also improve the ORR activity. While oxide overlayers can be fabricated by using other techniques (sputtering [136][137][138], infiltration [139][140][141]), the conformal nature of the ALD process may further help to enhance the stability of metallic electrodes. The stabilization mechanism of metal nanoparticles by the oxide overlayer may include: (1) anchoring of metallic nanoparticles to the substrate, (2) stabilization of unstable metal surface atoms, which may impede the physical merging, and (3) Ostwald ripening of metallic nanoparticles [136,[142][143][144][145][146].…”

First-Principles Modeling of Oxygen Adsorption on Ag-Doped LaMnO3 (001) Surface

“…In order to reduce the operation temperature down (e.g. 500ºC, Intermediate Temperature regime), use of catalysts is necessary [8]. The best catalyst for ORR is Pt or Ptalloys, which, however, is quite expensive.…”

“…The best catalyst for ORR is Pt or Ptalloys, which, however, is quite expensive. Recent experimental studies [8,9] suggested Ag as an alternative. Zhou and co-authors [10,11] in their theoretical calculations have shown that on the MnO2-terminated (001) LaMnO3 (LMO) surface Ag-doping significantly increases oxygen adsorption energy.…”