Atomic structure observations and reaction dynamics simulations on triple phase boundaries in solid-oxide fuel cells

Abstract

The triple phase boundary (TPB) of metal, oxide, and gas phases in the anode of solid oxide fuel cells plays an important role in determining their performance. Here we explore the TPB structures from two aspects: atomic-resolution microscopy observation and reaction dynamics simulation. Experimentally, two distinct structures are found with different contact angles of metal/oxide interfaces, metal surfaces, and pore opening sizes, which have not previously been adopted in simulations. Reaction dynamics simulations are performed using realistic models for the hydrogen oxidation reaction (HOR) at the TPB, based on extensive development of reactive force field parameters. As a result, the activity of different structures towards HOR is clarified, and a higher activity is obtained on the TPB with smaller pore opening size. Three HOR pathways are identified: two types of hydrogen diffusion processes, and one type of oxygen migration process which is a new pathway.

Microstructure and long-term stability of Ni–YSZ anode supported fuel cells: a review

“…It is supposed that various Ni/YSZ interfaces coexist in different energy states, and certainly the method of synthesis is crucial to define the grain orientation. These results confirm that preparation routes such as DSEs are essential to achieve high stability [74].…”

Metallic nanoparticle-on-mirror: Multiple-band light harvesting and efficient photocurrent generation under visible light irradiation

“…While the 3-nm-thick Au-based NPoM sample exhibits 13.29% integrated PEC efficiency in the visible spectral range, both 5-and 10-nm-thick Au NPoM samples almost vanish exhibiting PEC efficiencies of 0.34% and 0.39%, respectively. The latter indicates that the PEC efficiency is driven not only by the NP size but mainly by the available semiconductor metal catalyst three-phase (Au NP/TiO 2 /electrolyte) boundary [60,66]. Finite element numerical simulations verify that the enhancement of the electric field is localized at the metal/semiconductor/electrolyte boundary upon excitation (Fig.…”

Microstructure Evolution in a Solid Oxide Fuel Cell Stack Quantified with Interfacial Free Energy

“…Using Transmission Electron Microscopy (TEM) Nahor et al [21] measured Ni-YSZ interfacial energy at γ NiYSZ = 1.8-2.1 J m −2 depending on configuration. SEM measurements of SOFC atomistic structure suggest interface thickness of 0.242 nm [22]. Similarly, Chen et al [13], use interfacial energy ratio of γ NiYSZ :γ NiPore :γ YSZPore = 2.2:1.9:1.4 and these are the values which we employ in our study.…”