Formation, Performance, and Long-Term Stability of Nanostructured Ni-YSZ Thin Film Electrodes

Abstract

Nickel and yttria-stabilized zirconia (YSZ) composite anodes were fabricated by a powder-free, polymeric precursor-based process, in which Ni, Y, and Zr cations are redistributed by phase separation at the nanoscale, forming YSZ and Ni(O). Transmission electron microscopy/energy-dispersive X-ray spectroscopy analyses revealed for the first-time in the literature that the nanocomposite thin film Ni-YSZ anodes had microstructures consisting of alternating Ni and YSZ nanolayers. A pre-calcination step applied in the oxidized state enhanced the interconnectivity of the Ni and YSZ phases after reduction, which improved the electrochemical performance. Electrochemical and microstructural analyses showed that performance degradation upon long-term exposure to dilute hydrogen at 600 °C was closely related to Ni coarsening in general. Evidently, the pre-calcination step enhanced the performance stability of the anodes by strengthening the YSZ network and thus inhibiting Ni agglomeration. In addition, the deposition of a thin, electronically conductive CeO 2 overlayer on top of the Ni-YSZ anode inhibited the excessive agglomeration of Ni at the top surface. Our experiments showed that the pre-calcination of Ni-YSZ anodes in the oxidized state with a CeO 2 overlayer gave the highest electrocatalytic performance, i.e., a polarization resistance of 0.72 Ω•cm 2 at 600 °C, in dilute hydrogen, as well as the highest long-term performance stability.

Prediction of Dynamic Ni Morphology Changes in Patterned Ni-YSZ Anode with Physics-Informed Neural Networks

“…It has been reported that complex and tortuous YSZ network can impede Ni movement and can hinder Ni coarsening. 52 Another difference comes from the fabrication process. In the present study, Ni stripes are sputtered on the YSZ substrate, while Ni/YSZ cermet are fabricated through wet ceramic processes such as screen printing, slurry spraying, or tape casting of NiO and YSZ powders, followed by high-temperature sintering.…”

LSF films formed on YSZ electrolytes via polymeric precursor deposition for solid oxide fuel cell anode applications

“…However, Ni-based composites have several drawbacks. For example, Ni de-wets YSZ surface due to the high interfacial energy, which enables coarsening and migration of Ni, resulting in a shortened electrochemically active electrocatalyst-ionic conductor-gas triple phase boundary and thus, perfor-mance loss [1,2]. Ni is also prone to oxidation to NiO when the fuel gas flow is interrupted.…”

Rational Development of IT-SOFC Electrodes Based on the Nanofunctionalization of La0.6Sr0.4Ga0.3Fe0.7O3 with Oxides. Part 2: Anodes by Means of Manganite Oxide

“…One of them may be the development of SOFCs that can operate directly with hydrocarbons, which possess an already well-developed supply service. Traditional Ni–YSZ cermets are recognized as the state-of-the-art material when operated on hydrogen − owing to the unbeatable trade-off between the low cost of the materials and their great performances. However, the activity of Ni toward the formation of carbon leads to the poisoning of the anode by coking, affecting long-term operation. − …”